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The  Silver  Sunbeam: 


A  PRACTICAL  AND  THEORETICAL  TEXT-BOOK 

ON 

SUN  DRAWING  AND  PHOTOGRAPHIC  PRINTING : 

COMPREHENDING  ALL  THE 

"WET  AND  DRY  PROCESSES 

AT  PRESENT  KNOWN,  WITH 

Collodion,  Allien,  Gelatine,  fax,  Resin,  ana  Silver ; 

AS  ALSO 

Heliographic  Engraving,  Photolithography,  Photozincography,  Microphoto- 
graphy,  Celestial  Photography,  Photography  in  Natural  Colors,  Solar 
Camera  Work,  Tinting  and  Coloring  of  Photographs,  Printing 
in  Various  Colors ;  the  Carbon  Process,  the  Card-Pic- 
ture, the  Cabinet-Picture,  the  Vignette,  and 
Stereography. 

Br 

J.  TOWLER,  M.D., 

TROFFSSOR  OF  NATURAL  PHILOSOPHY  AND  CHEMISTRY. 
EIGHTH  EDITION. 

ENLARGED,  IMPROVED,  AND  ILLUSTRATED  WITH  NUMEROUS  WOODCUTS, 

And  containing  matter  written  by  Blanquart  Evrard,  John  W.  Draper,  M 
Carey  Lea,  R.  J.  Fowler,  Valentine  Blanc ard,  Major  Russell 
B.  J.  Satce,  Dr.  Hill  Norris,  M.  Clatjdet,  M.  Van  Monkhoyen, 
G.  Wharton  Simpson,  Jabez  Hughes,  Lake  Price,  and 
other  distinguished  writers. 


•'And  God  said,  Let  there  be  light:  and  there  was  light." 


NEW-YORK: 
E.  &  H.  T.  ANTHONY  &  Co.,  Publishers. 

LONDON :  TRUBNER  &  CO. 

1873. 


Entered,  according  to  Act  of  Congress,  in  the  year  1873,  by 

E.  &  H.  T.  ANTHONY  &  CO., 
In  the  Office  of  the  Librarian  of  Congress,  at  Washington. 


PREFACE  TO  THE  EIGHTH  EDITION. 


New  York,  June  1,  1873. 

The  increasing  popularity  of  the  Silver  Sunbeam,  and 
the  urgent  demand  for  it  everywhere  and  by  all  who  are 
interested  in  Photography,  has  resulted  in  the  publica- 
tion of  another  edition — the  Eighth — in  which  is  includ- 
ed such  additional  chapters  as  wTere  found  to  be  desirable 
and  necessary  to  render  the  Silver  Sunbeam  an  encyclo- 
paedia of  the  art  to  date. 

The  Eighth  Edition  contains  all  and  everything  of  the 
preceding  seven ;  and,  besides  the  valuable  and  interest- 
ing new  matter,  it  is  embellished  with  a  large  number 
of  illustrations  of  photographic  apparatus  in  present 
use,  with  brief  descriptions  of  the  same. 

It  is  a  gratification  to  know  that  the  Silver  Sunbeam 
continues  to  be  the  favorite  photographic  manual  with 
stock  dealers,  amateurs,  beginners,  and  practising  pho- 
tographers, and  that  its  pages  form  a  comprehensive 
and  intelligible  guide  in  every  branch  of  photography, 
and  for  all  classes. 

Some  errors  may  be  noticed  of  trifling  importance, 
but  they  are  such  as  will  be  readily  detected  by  any 
one  familiar  with  the  subjects  treated  of,  though  they 
will  be  of  no  disadvantage  to  others. 

The  Publishers. 


PEEFACE  TO  THE  'SEVENTH  EDITION. 


New-York,  April,  1870. 
We  are  again  called  upon  for  another  edition  of  The  Silver  Sun- 
beam— the  seventh.  We  will  say  nothing  of  the  great  success  of  the 
book,  or  of  the  fact  that  it  is  now  universally  admitted  to  be  the  standard 
work  on  the  art,  and  that  it  contains  information  and  instruction  in 
every  branch  of  Photography.  As  will  be  seen,  we  have  added  largely 
to  the  already  large  stock  of  information  contained  in  the  previous 
editions. ' 

We  give  several  new  chapters,  each  containing  a  variety  of  articles 
of  great  value  :  one  written  by  Herr  Albert,  about  his  new  Mechanical 
Printing  Process  ;  one  on  Sarony's  new  Photo-Crayon  Portraits  ;  one 
by  Gr.  Wharton  Simpson  on  Printing  with  Collodio -Chloride  of  Silver  on 
Paper  and  Opal  Glass  ;  Bovy 's  new  Process  for  Printing  on  Painted  Can- 
vas ;  an  article  from  Samuel  Fry  on  the  Advantages  of  a  Substratum  for 
the  Collodion  Film  ;  M.  A.  De  Constant's  new  Photo-Miniature  Process  ; 
a  New  and  Simple  Process  for  Enlarging,  by  W.  H.  Davies ;  H.  Baden 
Pritchard's  Method  of  Photographing  Machinery ;  an  article  from  Al- 
fred Hughes,  and  many  others  whose  names  it  is  unnecessary  to  men- 
tion here.  We  also  give,  in  one  page,  the  names  of  over  one  hundred 
celebrated  writers  on  photography,  whose  formulae  are  given  in  this 
work. 

Suffice  it  to  say,  that  the  additions  to  the  Seventh  Edition  of  The 
Silver  Sunbeam  will  be  considered  of  great  importance  by  all  photo- 
graphers and  amateurs,  and  be  an  incentive  to  many  to  purchase  the 
Seventh  Edition,  although  they  may  be  in  possession  of  some  of  the 
previous  ones. 

We  are  gratified  in  being  assured  by  stock-dealers  everywhere  that 
The  Sunbeam  is  as  salable  as  ever.  For  an  amateur  or  beginner, 
"  The  Sunbeam  "  is  always  recommended  as  the  best  authority  on 
the  art.  As  edition  after  edition  comes  from  the  press,  the  book  grows 
more  and  more  bulky.  We  can  find  nothing  in  the  work  which  we 
think  can  be  left  out  with  advantage  ;  and  with  each  edition  we  add  a 
large  amount  of  new  matter.  The  First  Edition  was  comprised  in  350 
pages.  The  present  edition  embraces  570  pages — an  increase  of  over 
sixty  per  cent  in  the  amount  of  matter  ;  and  we  have  therefore  advanced 
the  price  of  this  edition  to  three  dollars  per  copy,  which  is  an  increase 
of  only  twenty  per  cent,  and  an  increase  which  we  feel  fully  justified  in 
making. 

With  these  few  remarks  by  way  of  preface  to  the  Seventh  Edition, 
the  publisher  would  once  more  offer  his  thanks  to  the  trade,  and  the 
public  generally,  for  the  warm  reception  they  have  heretofore  given  to 
The  Sunbeam,  and  he  trusts  that  the  present  edition  will  also  meet 
with  their  approval. 


PREFACE  TO  TIE  SIXTH  EMTIO! 


The  last  edition  of  The  Silver  Sunbeam  having  been  entirely- 
exhausted,  and  the  demand  for  the  work  still  continuing,  it  becomes 
our  duty  as  well  as  pleasure,  to  issue  the  Sixth  Edition,  which  largely 
exceeds  all  the  previous  issues  both  in  the  quantity  and  variety  of  its 
contents. 

We  have  added  over  one  hundred  pages  of  entirely  new  matter, 
much  of  it  illustrated  with  woodcuts,  and  most  of  it  embracing  sub- 
jects not  before  treated  upon  in  this  work.  We  have  added  Nine 
new  Chapters,  each  chapter  embracing  a  variety  of  topics.  In  the 
first  part  of  the  work  we  have  placed  eighteen  pages  devoted  to  Ele- 
mentary Photography,  adapted  especially  to  the  wants  of  the  New 
Beginner.  We  publish  full  details  of  Mr.  Swan's  improved  Carbon 
Process,  as  given  by  him  the  past  year.  The  new  matter  published 
in  the  third  and  fifth  editions,  was  embraced  under  the  head  of  "  Ap- 
pendix this  we  have  divided  up  into  chapters,  with  a  suitable  run- 
ning head  on  each  page.  At  the  end  of  chapter  forty-seven,  we 
give  additional  information  on  the  important  subject  of  reducing 
photographic  wastes,  illustrated  with  woodcuts.  We  give  full  de- 
tails, illustrated  with  woodcuts,  of  the  process  of  Enlarging  by  the 
Solar  Camera ;  also  a  chapter  devoted  to  Failures ;  their  Or%m  and 
Remedies,  suitably  illustrated  by  eleven  woodcuts.  Full  details  of 
photographing  microscopic  objects,  photographing  on  canvas,  Cam- 
arsac's  new  process  of  Enameling,  or  Burning-in;  the  Serum  process 
for  enlarging  photographs,  and  numerous  other  processes  not  before 
published  in  The  Sunbeam,  the  whole  embracing  nine  chapters  and 
fifty-nine  woodcuts. 


PREFACE. 


It  has  been  our  aim  to  have  in  this  edition  everything  new  in  the 
Art  which  is  of  interest,  and  which  has  come  to  light  during  the  past 
two  years.  There  is  no  book  published  which  contains  near  as  much 
information  on  the  subject  of  Photography  as  is  embraced  in  the  five 
hundred  and  forty-five  pages  of  this  book ;  and  we  issue  this  Sixth 
Edition  in  the  confident  hope  and  expectation,  that  it  will  meet  the 
wants  and  desires  of  intelligent  Photographers  both  in  this  country 
and  in  England,  where  numerous  copies  have  been  sold.  With  this 
description  of  the  changes  and  improvements  made  in  the  present 
volume,  we  offer  the  work  to  the  operator  and  amateur,  trusting  that 
they  will  find  it  interesting  and  valuable. 

The  Publishes. 

New  York,  Jan.,  1869. 


PREFACE  TO  THE  FIFTH  EDITION. 


Four  editions  of  The  Sunbeam  have  been  exhausted  in  the  short 
space  of  three  years ;  and  on  entering  the  Fifth  Edition,  the  Publisher 
is  of  opinion  that  the  writer  of  this  work  ought  to  herald  its  reap- 
pearance with  some  prefatory  remarks.  This  is  the  most  irksome 
task  ever  imposed  upon  the  author ;  he  would  rather  march  twelve 
hours  a  day  in  a  tropical  climate  than  launch  out  eulogistically  on 
his  own  efforts  in  this  direction.  Eulogy  of  self  is  the  tenor  of 
every  preface.  The  success  of  those  efforts  is  to  be  attributed  to  the 
want  they  supply,  and  not  to  their  intrinsic  merit  as  an  original 
production.  The  work  has  acted  like  the  pill  of  the  medical  prac- 
titioner, who  is  capable  of  making  a  correct  diagnosis ;  but  the  reader 
must  look  upon  this  expression  as  laudation.  The  public  knew, 
every  photographer  knew,  that  a  practical  text-book  on  the  helio- 
graphic  arts  was  needed  on  this  side  the  Atlantic  :  this  was  the  diag- 
nosis. No  more  merit  could  be  attached  to  the  definite  determina- 
tion of  it  than  to  the  remarks  of  the  doctors  in  reference  to  the  un- 
fortunate passengers  on  the  steamship  England  ;  "  They  were  suffer- 
ing for  want  of  food,  of  pure  air,  and  of  more  room  to  stir  in  and 
food,  pure  air,  and  more  room  having  been  administered  and  assigned 
to  them,  and  the  reputed  cholera  having  vanished,  the  sanitary 
directors  are  regarded  as  very  meritorious  and  shrewd  medical  ad- 
visers. 

The  author  of  The  Sunbeam  stands  in  a  similar  relation  to  photo- 
graphers ;  he  has  thrown  more  light  into  their  dark-rooms,  prescribed 
numerous  recipes  for  the  practical  explanation  of  photography,  and 
defined  by  common  language  and  with  common-sense  what  before 
was  abstruse  and  mystical.  They  feel  the  benefit  of  his  instructions, 
and,  in  gratitude,  demand  a  new  edition  commensurate  with  the  ad- 
vances and  discoveries  of  the  photographic  art  and  science. 

In  accordance  with  this  request  the  work  has  been  enlarged  by  the 
addition  of  a  totally  new  appendix ;  but  the  original  work  has  been 
left  unchanged.  Changes  are  odious  to  authors,  who,  attached  to 
their  productions  as  to  their  offspring,  prefer  the  fabrication  of  new 
works  to  the  patching  up  of  old  ones.  Such  is  the  writer's  view . 
and  being  willing  to  cater  for  the  public  taste  and  wants,  he  will  edit 
an  entirely  new  work  the  moment  circumstances  require  it,  and  con- 
sign The  Sunbeam  to  the  shade. 

Geneva  Medical  College,  April  24,  1866. 


NAMES  OF  WRITERS. 


The  following  are  the  names 
mulae  are  given  in  this  work. 

ACKLAND. 

Anthony,  Henry  T. 

Blancard,  Valentine. 

Baldus. 

Bayard. 

Bertsch. 

Burnett. 

Beauregard. 

Bond. 

Berry. 

Becquerel. 

borlinetto. 

Britton. 

Bloede,  Victor  G. 
Bartholomew. 
Bur  well,  F.  W. 
Bolton. 

Claudet. 
Crookes, 
Champlouis. 
Chardon. 

Camarsac,  La  Fon  de. 

Caron. 

Castracan. 

Draper,  John  W. 
Draper,  Henry. 
Despratz. 
Dubosq. 
Donne. 
De  La  Rue. 
Deville. 
Duncan,  David. 
Drummond,  A.  J. 

EVRARD,  BLAITQUART. 

England,  W. 
Edwards. 


writers  on  photography,  whose  for* 


Fowler,  R.  J. 
Fargier. 
Fizeau. 
Forrest. 
Fox,  Thomas. 
Fink,  F. 

Gage,  William. 

Geoffray. 

Glover. 

Garnier. 

Girard. 

Hartnup. 
Hodgson. 
Haakman. 

Harrison,  William  H 
Herschel,  Sir  John. 
Hilaire,  David. 

James,  Sir  H. 

JOUBERT. 

Keene. 

Lea,  M.  Carey. 
Libois. 
Loewe. 
Legray. 
Larpey,  James. 

Molard,  Humbert  D. 

Mudd,  James. 

Mayo. 

Marion. 

Motileff. 

Matthiesen. 

moitessier. 

Maddox. 

Meinerth,  Carl. 


NAMES 


Newton,  H.  J. 

Niepce. 

Neuman. 

Norms,  Dr.  Hill. 

Osborne-Obernetter. 

Price,  Lakh 
Prichard. 

POUNCEY. 
PoiTEVTN. 

Phipson. 

Bussell,  Major. 

Sayce,  B.  J. 

Salmon. 

Sutton. 

Secchi. 

Schwartz. 


of  writers. 


Simpson,  G-.  Wharton. 

St.  Clair. 

sonstadt. 

Swan,  Joseph  W. 

Selle. 

Tunny,  James  GK 
Taupenot. 

TlLLARD. 

Talbot. 
Towler,  John. 

Verity. 

Van  Monckhoven. 

Wortley,  Lt.  Col.  Stuart. 
Wenderoth,  F.  A. 
Woodbury,  Walter. 
Willis,  William. 
Woodward. 


CONTENTS  OF  "  ELEMENTARY  PHOTOGRAPHY." 


We  give  here  the  contents  of  that  portion  of  this  work  entitled 
Elementary  Photography,  which  is  first  published  in  this  edition, 
and  the  pages  of  which  are  numbered  at  the  bottom  from  1  to  18 
inclusive. 

PAGE. 

Introduction,  1 

Apparatus  necessary,  3 

Chemicals  necessary,  4 

How  to  Prepare  the  Dark-Room,  5 

How  to  Begin  Work,  .       .       .  .6 

How  to  take  Glass  Positives,  Ferrotypes  and  Ambrotypes,       ...  8 

How  to  take  Negatives,  13 

How  to  Varnish  the  Negative,  18 

Positive  Printing  on  Plain  and  Albumenized  Paper,  18 


Additional  information  on  the  above  subjects  will  be  found  as 
follows : 

PAGE. 

List  of  Photographic  Outfit,  25 

The  Glass-House,  etc.,  27 

The  Camera  and  the  Lens,  34 

The  Dark-Room,  46 

The  Work-Room,  49 

Chemicals,  51  to  125 

The  Collodion  Positive  Process,  127 

The  Collodion  Negative  Process,   144 


CONTENTS. 


CHAPTER  I.  1 

PAG1 

History  op  Photography,  «    ,  9 

CHAPTER  H. 

Preliminary  Observations,   21 

List  of  Photographic  Outfit,   25 

CHAPTER  III. 

Specialties  in  reference  to  the  Articles  in  the  preceding  Chapter — the  Glass- 
house, etc.,   27 

CHAPTER  IV. 

Specialties  continued— The  Camera  and  the  Lens,   34 

To  find  the  Principal  Focus  of  a  Lens,   36 

To  find  the  Equi-distant  Conjugate  Foci  of  a  Lens,   36 

To  find  the  Comparative  value  of  two  Lenses  or  Combinations  which  produce  the 

same  sized  image  of  an  object  at  the  same  distance,   3T 

To  find  the  magnifying  power  of  a  Lens  or  Combination,   37 

To  find  the  comparative  magnifying  power  of  Lenses  or  Combinations,   3T 

To  find  a  Single  Lens  equivalent  in  power  to  a  Compound  Lens,   37 

To  ascertain  whether  a  Combination  is  corrected  for  Spherical  Observation,   37 

To  ascertain  whether  a  Lens  or  Combination  is  corrected  for  Chromatic  Observation,  38 

How  to  buy  a  good  Lens,   39 

CHAPTER  V. 

Specialties  continued— The  Camera,   42 

CHAPTER  VI. 

Specialties  Continued,   46 

Dark-Room,   46 

Work-Room,   49 

CHAPTER  VII. 

Collodion,   51 

Preparation  of  Pyroxyline,   52 

Formula,  No.  1,  for  the  preparation  of  Pyroxyline,   53 

Formula,  No.  2,  for  the  preparation  of  Pyroxyline,   55 

Formula,  No.  3,  for  the  preparation  of  Pyroxyline,   55 

Formula,  No.  4,  for  the  preparation  of  Pyroxyline,   55 

CHAPTER  VIII. 

Ether  and  Alcohol,     56 

Ethyle  Group,   56 

Ether,  ,    53 

Alcohol,  .   59 

Decomposition  of  Collodion,   61 

Preparation  of  Glycyrrhizine,   63 

Preparation  of  Nitro-glucose,   63 

CHAPTER  IX. 

Collodion  Sensitizers — Iodides  and  Bromides,   65 

CHAPTER  X. 

Preparation  of  the  Iodides,   69 

Iodine,   69 

Properties  of  Iodide,   70 

Preparation  of  Ilydriodic  Acid,,   70 

Iodide  of  Barium,   71 

Iodide  of  Calcium,  ,   72 

Iodide  of  Lithium,   72 

Iodide  of  Potassium   72 

Iodide  of  Sodium  and  Iodide  of  Ammonium,  ,   73 

Iodide  of  Cadmium,   73 

Impurities  of  the  Iodides,.  »   73 

Tests  of  the  purity  of  the  Iodides,   74 


X 


CONTENTS. 


CHAPTER  XI.  PAOB 

Bbomhtb,   75 

Preparation  of  Bromine,   Jo 

Hydrobromic  Acid,   76 

Bromides,     £6 

Preparation  of  the  Chlorides,   76 

Preparation  of  Chlorine,    77 

Properties  of  Chlorine,   77 

Chloride  of  Lime— Chlorinetted  Lime,  etc.,   73 

CHAPTER  XII. 

Normal  or  Plain  Collodion,  Iodized  Collodion,  Bromo-iodized  Collodion,   79 

Bromo-iodizing  Solutions,   SO 

P(  rmula  of  Lieut.-Col.  Stuart  Wortley,   SO 

Ommeganck's  Formula  for  Portraits  and  Landscapes,   SI 

Formulas  of  Disderi,   81 

Formula  for  copying  Collodion,   83 

CHAPTER  XIII. 

Silver — Salts  of  Silver,   84 

Properties  of  the  Nitrate  of  Silver,   8S 

Photographic  properties  of  the  Nitrate  of  Silver,   88 

Preparation  of  the  other  Salts  of  Silver,     90 

Hyposulphite  of  Silver,   90 

Iodides  of  Silver,   90 

Iodide  of  Silver  for  the  Silver  Bath,   90 

Bromide  of  Silver,   91 

Chloride  of  Silver,   92 

Photographic  properties  of  the  Chloride  of  Silver, . . . .'   93 

Other  uses  of  the  Chloride  of  Silver,   93 

CHAPTER  XIV. 

Reducing  Agents — Developers,   94 

Iron  Developers,     97 

Nitrate  of  the  Protoxide  of  Iron,   97 

Sulphate  of  the  Protoxide  of  Iron,     9T 

Double  Sulphate  of  Iron  and  Ammonia,   98 

Sulphide  of  Iron,   98 

Tannic  Acid — Gallic  Acid — Pyrogallic  Acid,   98 

Preparation  of  Tannic  Acid,   99 

Preparation  of  Gallic  Acid,   100 

Preparation  of  Pyrogallic  Acid,   101 

Acids  in  Developing  Solutions,   102 

Acetic  Acid,   103 

Formic  Acid,  „  104 

Photographic  uses  of  Formic  Acid,   105 

Citric  Acid,   105 

Citrate  of  Soda,  106 

Photographic  uses  of  Citric  Acid,   106 

Tartaric  Acid,   10T 

Preparation  of  Tartaric  Acid,   107 

CHAPTER  XV. 

The  Nitrate  of  Silver  Bath,  109 

Preparation  of  the  Sensitizing  Solution,  „  110 

Formula,  No.  1,  110 

Formula,  No.  2,   Ill 

Formula,  No.  3,  Ill 

CHAPTER  XVI. 

The  Developing  Solutions,  114 

Sulphate  of  Iron  Developer,  Formula  No.  1,  for  Ambrotypes  and  Melainotypes,  114 

Formula,  No.  2,  for  Negatives,   115 

Formula,  No.  3,  for  Negatives,  115 

Formula,  No.  4,  for  Negatives,  ]  115 

Disderi's  Developer,  115 

Lieut.-Col.  Stuart  Wortley's  Developer,  ....  116 

BKeynier's  Developer,  116 

Hockins's  Developer*,   .  116 

Waldack's  Formulas,  [   116 

CHAPTER  XVII. 

Fixing  Solutions,   119 

Cyanogen,   118 


CONTENTS.  xi 


PAGE 

Preparation  jf  Cyanogen,   118 

Hydrocyanic  Acid — Prussic  Acid,  119 

Cyanide  of  Potassium,. ,   119 

Sulphocyanide  of  Potassium,    12D 

Sulpbocyanide  of  Ammonium,   120 

Hydrosulphocyanic  Acid,   120 

Hyposulphite  of  Soda,  .   120 

Formulas  for  fixing  Solutions,   121 

Formula,  No,  1,  with  Cyanide  of  Potassium,   121 

Formula;  No,  2,  with  Hyposulphite  of  Soda,   121 

Formula,  No.  3,  with  Sulphocyanide  of  Ammonium,  121 

CHAPTER  XVIII. 

Intensifies,  122 

Preparation  of  Bichloride  of  Mercury — Corrosive  Sublimate,  125 

Preparation  of  Sulphide  of  Potassium — Hepar  Sulphuret,  125 

Preparation  of  Sulphide  of  Ammonium,  ,  125 

CHAPTER  XIX. 

Wet  Collodion  Process,  127 

Collodion  Positives — The  Melainotype — the  Ambrotype,  127 

Ambrotype,   128 

First  Subdivision — Preparing  the  Glass,   128 

Second  Subdivision — Coating  the  Glass  with  Collodion,  129 

Third  Subdivision — Sensitizing  the  Collodion  Film,  130 

Fourth  Subdivision — Exposing  the  Plate  in  the  Camera,  131 

Fifth  Subdivision — Developing  the  Picture,   131 

Formula  for  Developers,   132 

Sixth  Subdivision — Fixing  the  Image,  133 

Remedy  for  Fogginess,  133 

Seventh  Operation— Drying  the  Plate,   135 

Formula  for  subdued  Contrasts,     136 

Eighth  Operation— Coloring  the  Picture,  136 

Ninth  Operation — Varnishing  the  Image,  136 

Varnishes,   137 

Tenth  Operation — Background  for  Collodion  Positives,   138 

Black  Varnishes,   138 

CHAPTER  XX. 

Alabastrine  Positives,  140 

Alabastrine  Solution,   140 

CHAPTER  XXI. 

Melainotype — Ferrotype,  142 

Operation,  142 

CHAPTER  XXII. 

Collodion  Negatives,  144 

Negative  Developers,   145 

Formula,  No.  1,  Iron  Developer,  145 

Formula,  No.  2,  Pyrogallic  Acid  Developer,   146 

Fixing  Solutions  for  Negatives,  147 

Formula,  No.  1 — Hyposulphite  of  Soda,   147 

Formula,  No.  2 — Cyanide  of  Potassium,   147 

Intensifying  or  Re-developing  Process,  147 

Formula,  No.  1 — Depositing  Fluid,   147 

Formula,  No.  2— Stock  Bottle  of  do.,   147 

Depositing  Operation,  147 

Intensifying  Operation,   147 

Formula,  No.  1^-Nitrate  of  Silver,   147 

Formula,  No.  2— Pyrogallic  Acid,  (Stock,)   148 

Formula,  No.  3—      "         "   148 

Varnish — Formula  fordo.,   149 

CHAPTER  XXIII. 

Transfer  Process  of  Collodion  Positives  on  Japanned  Leather,  Linen,  Paper,  etc.  150 

Black  Japan,  150 

Transfer  Paper,    151 

CHAPTER  XXIV. 

Collodion  Positives  on  Glass  by  transmitted  Light — Transparent  Positiykc,.  . . .  153 
CHAPTER  XXV. 

Enlargement  of  Negatives  by  the  Ordinary  Camera,  157 

Reflectors  used  as  Condensers  of  Light,  15S 


xii  OOXTENTS. 

CHAPTER  XXVI.  PAG1 

T&ANSFA PENT  POSITIVES  BY  CONTACT  BY  TIIE  WET  PROCESS,    159 

CIIAPTER  XXVII. 

Collodion  Negatives  or  Positives  copied  from  Collodion  or  Paper  Positives,...  160 
CIIAPTER  XXVIII. 

Stereographic  Negatives  and  Landscape  Photography,     164 

Instantaneous  Stereographs,   166 

Instantaneous  Process  of  Lieut.-Col.  Stuart  Wortley,   16T 

Valentine  Blanchard's  Bromo-iodized  Collodion,   163 

Hockins's  Iodized  Collodion,   169 

Claudet's  Developer,   169 

Instantaneous  Shutters,   169 

CHAPTER  XXIX. 

Negatives  on  Paper,     171 

The  Talbotype  or  Calotype  Process,   171 

To  Sensitize  Calotype  Paper,   171 

Fixing  of  the  Negative,.   172 

Wax-Paper  Process  of  Legray,   173 

Geoffray's  Process  with  Cerolein  for  taking  Paper  Negatives,   178 

Turpentine  and  Wax  Process  of  Tillard,   179 

Wet  Paper  Negative  Process  of  Humbert  de  Molard,   180 

Improved  Calotype  Process  by  Prichard,   180 

CHAPTER  XXX. 

Printing  on  Plain  Paper,  on  Albumenized  Paper,  on  Arrow-Root  Paper,   182 

Description  of  the  Materials  tised  in  Positive  Printing,. ,   183 

Albumen,   184 

Gelatine,   185 

Amylaceous  or  Non-Azotized  Substances,   186 

Starch,   186 

Gum- Arabic     187 

Chloride  of  Gold,   187 

Nitrate  of  Uranium,   189 

Acetate  of  Soda,  Citrate  of  Soda,  Phosphate  of  Soda,   190 

Carbonate  of  Soda,     190 

Carbonate  of  Lime,   190 

CHAPTER  XXXI. 

Manipulation  of  Positive  Printing,   192 

Preparation  of  Salted  Paper,   192 

Preparation  of  the  Albumenized  Paper,   194 

Preparation  of  Arrow-Root  Paper,   195 

Formula  for  Salting  Solution,   195 

Sensitizing  Bath,   196 

Formula  for  the  Plain  Silver  Solution,   196 

Formula  for  the  Ammonio-nitrate  of  Silver  Solution,   197 

Fuminating  Process,  .   198 

CHAPTER  XXXII. 

The  Printing  of  Sensitized  Paper,   200 

Toning  of  the  Prints,   201 

Formulas  for  Toning  Solutions,   202 

Fixing  Solution,   203 

Self-acting  Photographic  Washing-Machine,   205 

Mounting  of  Photographs,  ,   205 

What  to  do  with  the  Clippings,   207 

Mounting  Stereographs,.   20T 

CHAPTER  XXXIII. 

Bertrand's  New  Process  for  Positive  Printing,  «    209 

Glover's  Resinized  Printing  Process,   210 ,» 

CHAPTER  XXXIV.  * 

Printing  by  Development,  -   218 

Second  Method  of  Printing  by  Development,  with  a  Chloride  and  a  Bromide,..  213 

Third  Method  of  Printing  by  Development,  with  an  Iodide,   245 

Formula  for  Salting  Solution,   .  215 

Method  of  Sensitizing  by  Means  of  Nitrate  of  Uranium,  (The  Process  of  Niepce 

de  Saint  Victor,)   .....  ,   216 


CONTENTS.  xiii 


CHAPTER  XXXV.  pagi 

The  Card-Picture,  ,  . . .  ,  218 

Lenses  for  the  Card-Picture,  ,  219 

Development,  ,  219 

Fixing,  221 

Printing  of  Card-Pictures,  222 

Vignette  Printing,  ,  223 

Tuning,  Fixing  and  Mounting,  224 

On  the  Tinting  and  Coloring  or  Photographs,  224 

Colors  used  most  frequently,,  . ...   225 

Other  indispensable  articles. . . ,  225 

Coloring  of  a  Portrait,  225 

Coloring  of  the  Face,   226 

Blonde  hair,  chestnut-coltfred  hair,  black  hair,  227 

Gi-ay  hair,  red  hair,  white  hair,  228 

Blue  drapery,  green  drapery,  red  drapery,  rose-colored  drapery,  brown  drapery,  pink 

drapery,  white  drapery,  yellow  drapery,  229 

Pearl  Gray,   230 

Violet,   230 

Background,   930 

How  to  imitate  Metals,  etc.,  with  colors,  230,  231 

CHAPTER  XXXVI. 

Dry  Collodion  Process — Dry  Processes,    232 

The  Albumen  Process,   233 

Formula  for  Iodized  Collodion,   233 

Formula  for  Bromo-Iodized  Collodion,   234 

Drying  Process,   235 

Sensitizing  the  Film,   235 

Exposure  in  the  Camera,   236 

Development  of  the  Image,  -   23T 

Taupenot  Process — Collodion-Albumen  Process,   23T 

Preparation  of  the  Glass  Plates,   238 

Formula  for  the  Collodion,   238 

Sensitizing  of  the  Taupenot  Plates,   239 

Exposure,   239 

Development,   239 

Fixing  of  the  Taupenot  Plates,   240 

Modified  Albumen  Process,  by  James  Larpey,  ,   240 

Modified  Collodio-Albumen  Process,  by  James  Mudd,   241 

Fothergill  Process,   242 

CHAPTER  XXXVII. 

Dr.  Hill  Norris's  Process — Gelatine  Process,   244 

Preservative  Solution,  ,  244 

Tannin  Process  of  Major  Russell,  245 

The  Tannin  and  Honey  Process,  248 

Resin  Process,   249 

Sutton's  Rapid  Dry  Process,  250 

Keene's  Rapid  Dry  Process,     250 

CHAPTER  XXXVIII. 

Printing  of  Transparent  Positives  by  the  Dry  Process,   252 

To  take  copies  of  any  given  size,   253 

Table  for  enlarging  or  diminishing  Photographs,   256 

Application  of  the  preceding  table,   251 

MlCROPHOTOGRAPHY  AND  MaCROPHOTOGRAPHY,  257 

Solar  Microscope,   . ,  257 

How  to  find  the  point  where  the  Lens  is  to  be  placed,   260 

MACROPHOTOGRAPHY,  OR  THE  ART  OF  TAKING  ENLARGED  PHOTOGRAPHS,   262 

The  Negative  for  enlargement,  262 

The  quality  of  the  Negative,  '.  262 

CHAPTER  XXXIX. 

Thb  Daguerreotype,   268 

First  operation,  or  the  cleaning  and  polishing  of  the  Silvered  Plates,   268 

Second  operation,  or  the  Sensitizing  of  the  Silvered  Plate,   269 

Third  operation,  or  the  exposure  to  light,  269 

Fourth  operation,  or  Developing  by  the  Vapor  of  Mercury,   270 

Fifth  operation,  or  the  Fixing  of  the  developed  Image,   270 

Sixth  operation,  or  the  Toning  with  Gold,   271 


xiv 


CONTENTS. 


CHAPTER  XL. 

Printing  without  the  Sal^s  of  Silver,   272 

Process  with  the  Salts  of  Iron,  272 

(VAN  (TYPE,   273 

CRTS  TYPE,   273 

Process  with  the  Salts  oj?  Uranium,  273 

Pr  ioess  for  Red  Pictures,   274 

P  loi  ESS  for  Green  Pictures,   274 

Process  for  Violet  Pictures,  274 

Process  for  Blue  Pictures,   275 

Carbon  Process,   275 

Poungt^s  Process,   277 

Podnct's  New  Carbon  Process,   277 

Processes  of  Salmon  and  Garnier,   278 

Fakgier's  Process,   280 

Carbon  Processes  with  the  Salts  of  Iron,   2S1 

Process  with  Sesquichloride  of  Iron  and  Tartaric  Acid,   281 

To  Transfer  the  Carbon  Print  from  Glass  to  Paper,   283 

Printing  directly  on  Paper  by  means  of  the  Sesquichloride  of  Iron  and  Tartaric 

Acid   285 

Photographic  Engraving,   286 

Engraving  on  the  Daguerreotype  Plate,   286 

Process  of  Fizeau,   287 

Process  of  Talbot,   288 

asphalto-type  of  nlcephore  nlepce,   291 

Etching  on  Glass,   296 

Negre's  Process  for  Heliographic  Engraving,  »   296 

Copies  for  the  Engraver  to  work  from,  296 

Photo-Lithography  and  Photo-Zincography,   297 

asph^lto-pnoto-llthographic  process,     297 

Bichromo-Photo-Lithographic  Processes  of  Poitevin,   299 

Photo-Typographic  Process  of  Poitevin,  300 

Photo-Lithographic  Process  of  Newton,    300 

Photo-Zincography  by  Colonel  Sir  H.  James,  R.  E. ;  and  Photo-Lithography  by  Mr. 

Osborne,   301 

Photo-Pap yrogra phy  by  Colonel  Sir  H.  James,  R.  E.,  308 

On  the  production  of  Photographs,  etc.,  on  Glass  in  Enamel  Colors  by  Joubert,.  .  308 

CHAPTER  XLI. 

Stereoscopicity,  ,   310 

Strabonic  Stereograph   316 

..  319 

CHAPTER  XLII. 

Celestial  Photography,   320 

CHAPTER  XLIII. 

Heliochromy,  or  the  Art  of  taking  Photographs  in  Natural  Colors,   323 

CHAPTER  XLIV. 

Imperfections  in  Collodion  Negatives  and  Positives  and  their  Remedies.  326 

Fogginess,  .*  326 

Spots  and  Apertures,   82S 

Ridges  and  Undulating  Lines,   330 

Streaks  and  Stains,   331 

Feebleness  of  the  Image  or  Deficiency  of  Contrast,   331 

Harshness  or  Excess  of  Contrast,   332 

Imperfect  Definition,.."   332 

Solarizration,   332 

Tender  and  Rotten  Films,  332 

Imperfections  in  Paper  Prints,   333 

CHAPTER  XLV. 

Swan's  Improved  Carbon  Process,   337-362 

Van  Monkhoven's  Cuprammonium  Process,   342 

CHAPTER  XLVI. 

Improvements  in  the  Tannin  Process,   t  #  345 

The  Alkaline  Developer,   """"**!"  351 

fannin  as  a  Sensitizer,  " "  " ' '  353 

Cliromo-Photography,  m  m  [  ]  *  *  35(5 

process  without  the  Salts  of  Silver,  358 

Celestial  Photography,  860 


CONTENTS. 


XV 


H 


CHAPTER  XLVII. 

The  Wothlytype,  . .'  365 

Sutton's  Dry  Process,  *   363 

The  Raisin  Process,  373 

A  Reliable  Tannin  Process,  877 

Russell's  Improved  Tannin  Process,   382 

Modified  Fothergill  Process,   385 

Haakman's  Process,  387 

The  Collodio-Broraide  Process,.   389 

The  Porcelain  Picture,  or  Opal  type,  392 

The  Collodio-Chloride  Process,   399 

To  take  an  Opal  Picture  by  Contact,  : .  402 

The  Eburneum  Process,  4C3 

The  Eburneum  Background,  s . .  405 

Glazed  Collodion  Positives,   407 

"lazed  Photographs,   403- 

How  to  take  Photographs  by  Magnesium  Light,  412 

Magnesium,   413 

The  Duplex  Type,  417 

The  Hellenotype,   419 

The  Ivorytype,  ,   420 

Reduction  of  Wastes  and  Residues,   421 

Collo-Protosulphate  of  Iron  Developer,  425 

The  Collo- Ferric  Developer,   426 

Photo-Mezzotint  Printing,  ,   427 

Photo-Relief  Printing,  429 

The  Foxtype,.,   431 

Selle's  Intensifying  Solution,  432 

Photographic  Residues,   433 

CHAPTER  XLVIII. 

The  Solar  Camera  and  Solar  Enlargements,   443 

CHAPTER  XLIX. 

Failures  :  The  Origin  and  Remedies,  454 

CHAPTER  L. 

Photomicrography,   465 

Photographing  on  Commas,   467 

Enameling,  or  Burning-in  Process,  470 

Printing  on  Ivory,  475 

Serum,  or  Whey  Process  for  Enlarging,  47T 

CHAPTER  LI. 

Copying  Engravings,  (  480 

Washed  Plate  Process,  4S2 

The  Morphine  Process,  482 

The  Coffee  Process,  /  483 

Obtaining  Positives  in  Colors,   484 

CHAPTER  IH.  - 

Sel  Clement,    486 

Mezzotint  Photographs,   489 

The  Magic  Photograph,  490 

Cabinet  Portraits,  492 

Gage's  Improved  Photographs,  492 

CHAPTER  LIII. 

Newton's  Dry  Processes,   494 

The  Tea  Process,   494 

Newton's  Opium-Tannin  Process,  496 

Description  of  Apparatus,  497 

CHAPTER  LIV. 

Weights  and  Measures,   499 

CHAPTER  LV. 

Comparison  of  Thermometric  Indications  in  the  Principal  Thermometers  in  use,..  502 
CHAPTER  LVI. 

Comparison  op  Hydrometric  Specific  Gravity  Indications,   504 

CHAPTER  LVII. 

Table  of  the  Elements  of  Matter,  with  their  Symbols  and  Chemical  Equiva- 
lents, 506 


xvi 


CONTENTS. 


CHAPTER  LVIII. 
ADDITIONS  TO  THE  SEVENTH  EDITION. 


ITerr  Albert's  Mechanical  Printing  Process,  507 

Sarony's  Photo-Crayon  Portraits,   509 

Printing  with  Collodio-Chloride  of  Silver  on  Paper  and  Opal  Glass,   510 

A  new  Process  for  Printing  on  Painted  Canvas,   512 

CHAPTER  LIX. 

On  the  Aptantages  of  a  Substratum  for  the  Collodion  Film,  '  514 

Chromo-Photography  or  Photo-Miniature,   515 

A  Simple  Apparatus  for  Enlargements,.  .   518 

How  to  Photograph  Machinery,  521 

CHAPTER  LX. 

How  to  make  Ripe  Collodion  at  once,   523 

Stippling  Glass  in  the  Studio,  524 

An  easy  and  certain  Method  of  Printing  on  Wood  Blocks,   526 

The  new  Calotype  Process,   527 

Indexes  to  each  Edition,  633 


TO  THE  READER. 


There  have  been  some  complaints  that  in  the  previous 
editions  of  The  Silver  Sunbeam,  the  introductory  part  was 
too  complicated  for  the  pupil  who  had  no  knowledge  what- 
ever of  the  Art  of  Sun  Drawing;  that  before  coming  to  the 
simple  details  of  the  Positive  Process,  or  the  art  of  taking 
an  Ambrotype,  he  was  obliged  to  read  through  one  hun- 
dred and  twenty  pages,  devoted  to  the  History  of  the  art, 
the  theory  of  Lenses,  how  to  find  the  congugate  foci 
of  a  Lens,  etc.;  all  about  the  Camera,  the  dark-room, 
work-room,  etc.  Then  the  pupil  must  learn  the  nature 
of  all  the  Chemicals  used  in  the  art :  the  Iodides  and  Bro- 
mides of  Barium,  Calcium,  Lithium,  Potassium,  etc.;  the 
Chlorides;  Salts  of  Silver;  Acids;  Developers;  Intensifi- 
es, and  many  others— all  these,  although  of  great  import- 
ance to  the  photographer,  come  rather  hard  and  are  very 
discouraging  to  the  new  beginner.  He  does  not  care  for 
all  this  information  on  the  start ;  he  wishes  to  know  what 
apparatus  and  chemicals  are  necessary,  and  how  to  use 
them;  he  does  not  care  how  they  are  made;  he  will,  how- 
ever, need  all  this  information  after  he  has  learned  to  take 
a  picture,  and  he  will  then  read  it  with  a  relish,  and  un- 
derstandingly.  The  Publisher,  therefore,  in  order  to  ac- 
commodate New  Beginners,  has  thought  best  to  insert,  as 
an  introductory  chapter,  some  simple  instructions  in  the 
Art,  much  of  which  is  written  by  Jabez  Hughes,  of  Eng- 
land, one  of  the  best  artists  and  writers  in  that  country. 
These  instructions  are  plain,  simple  and  easily  compre- 
hended by  the  learner. 

Additional  information  on  the  art  of  taking  an  Ambro- 
type, or  any  kind  of  Positive  Picture,  will  be  found  com- 
mencing on  page  127  of  this  book.  There  also  will  be 
found  full  directions  on  the  Collodion  or  Negative  Process, 
and  every  other  process  known  in  the  Art.  After  reading 
and  practicing  this  preliminary  part  of  the  book,  the  pupil 
will  be  better  prepared  for  the  remainder. 


ELEMENTARY  PHOTOGRAPHY 


INTRODUCTION. 

We  propose,  in  a  simple  and  familiar  manner,  to  intro- 
duce the  reader  to  the  wondrous  and  fascinating  Art  of 
Photography.  We  take  for  granted  that  you  are  entirely 
unacquainted  with  it,  and  that  you  are  anxious  to  learn. 
Before  proceeding,  however,  to  the  practical  portion,  we 
wish  to  impress  on  your  mind  a  few  of  the  leading  prin- 
ciples. 

The  word  Photography  means  drawing,  engraving,  or 
writing  by  Light. 

You  are  doubtless  aware  that  white  light — light  from 
the  sun,  for  instance — is  composed  of  three  different  colors 
— Yellow,  Red,  and  Blue:  it  also  possesses  three  distinct 
properties — Illuminating,  Heating,  and  Chemical  powers. 
These  three  powers  are  singularly  connected  with  the  three 
colors.  The  Illuminating  property  exists  mainly  in  the 
Yellow  rays — the  Heating  property  in  the  Red — and  the 
Chemical  in  the  Blue  or  Violet  rays. 

With  the  Illuminating  power  you  are  daily  familiar;  the 
July  sun  gives  certain  proof  of  its  Heating  power;  and  it 
is  your  present  purpose  to  learn  that  all  Photography  is 
based  on  its  Chemical  power. 

For  the  full  explanation  of  these  facts  we  must  refer  you 
to  Hunt's  Besearches  on  Light ;  in  that  excellent  work  is 
detailed  in  a  most  satisfactory  manner  the  threefold  func- 
tion of  a  sunbeam — to  illuminate,  to  heat,  and  to  produce 
chemical  change.    That  these  three  properties  are  distinct 

1 


INTRODUCTION. 


from  each  other  is  proved  by  their  being  separable  from 
each  other.  Thus,  black  glass  stops  the  illuminating  and 
the  chemical  rays,  but  allows  the  heating  rays  to  pass 
through ;  dark  blue  glass  arrests  the  heating  and  illumin- 
ating rays,  but  allows  the  chemical  ones  to  get  through; 
while  yellow  or  orange  glass  admits  light  and  heat,  but 
d9nies  passage  to  the  chemical  rays. 

Strictly  speaking,  then,  it  is  not  Light — the  illuminating 
agency — that  is  the  cause  of  photographic  action,  but  an 
active  principle  associated  with  it,  and  which  is  connected 
23i*incipally  by  the  weakest  illuminating  and  even  invisible 
rays.  This  Photographing  Power,  then,  that  is  associated 
with  Light,  but  which  is  not  Light,  is  termed  Actinism. 

The  daily  experience  of  every  photographer  proves,  that 
though  these  two  active  principles,  Light  and  Actinism, 
are.  constantly  associated  together,  yet  that  they  often  exist 
in  very  different  proportions  to  each  other.  There  may  be 
a  brilliant  light  with  but  moderate  actinic  power,  or  a  dull 
light  and  considerable  photographic  energy.  In  the  au- 
tumn, when  the  sun's  light  and  heat  are  at  their  maximum, 
the  actinic  power  is  by  no  means  great.  In  winter,  though 
the  light  be  rather  bright,  the  photographic  power  is  al- 
ways dull;  while  in  early  spring,  before  the  sun  has  ac- 
quired his  full  strength,  the  actinic  influence  is  relatively 
the  most  powerful  in  the  wThole  year. 

But  in  photographing  from  colored  objects,  these  facts 
will  be  more  strongly  impressed  on  your  mind.  When 
brilliantly-lighted  yellow  objects  "  come  out "  dark,  and 
dimly-lighted  blue  ones  will  appear  bright,  you  will  re- 
member the  reason — that  the  former  reflect  abundance  of 
light,  and  but  little  actinism  ;  whereas  the  latter  throw 
back  little  light,  but  much  actinism:  and  that  Actinism, 
not  Light,  is  the  real  picture-producing  power. 

The  general  term  Photography  embraces  many  proces- 
ses of  producing  jnctures,  but  the  particular  method  we 
intend  teaching  you — the  Collodion  Process — has  sup- 
planted nearly  all  others,  it  being  not  only  the  most  per- 
fect and  comprehensive,  but  also  the  most  simple. 

Pictures  by  this  process  are  taken  on  glass,  and  are 
either  Positive  or  Negative.  These  terms  will  be  explained 
hereafter,  when  the  processes  are  described;  and  it  is  only 
necessary  now,  before  we  commence  actual  operations,  to 
impress  on  you  that  photography,  from  beginning  to  end, 
consists  of  a  series  of  delicate  chemical  experiments.  The 
successful  execution  of  these  depends  apparently  on  many 

2 


APPARATUS  AND  CHEMICALS  NECESSARY. 

minute  causes,  which,  if  attended  to,  will  produce  the  de- 
sired end,  but  which,  if  neglected,  either  from  ignorance 
or  carelessness,  will  as  certainly  cause  failure  and  disap- 
pointment. 

You  must  be  very  exact  in  mixing  your  solutions,  and 
in  using  only  perfectly  clean  vessels  to  put  them  in. 

Cultivate  the  habit  of  noticing  carefully  all  that  you  do ; 
for  as  there  is  no  such  thing  as  chance  in  Photography, 
you  must  clearly  understand  that  when  you  fail,  you  do 
something  different  to  when  you  succeed,  and  that  this 
something  causes  the  failure.  As  your  natural  desire  will 
be  to  avoid  failures,  you  must  try  to  discover  these  causes, 
that  you  may  avoid  them;  and  if  you  proceed  in  this  man- 
ner you  will  certainly  become  a  good  and  intelligent  Pho- 
tographer. 

APPARATUS  AND  CHEMICALS  NECESSARY. 

The  first  thing  is  to  obtain  a  set  of  Apparatus.  Begin- 
ners too  frequently  get  a  common  cheap  one,  and  are  sur- 
rounded with  unnecessary  difficulties  from  this  cause  alone. 
There  is  no  reason  that  the  apparatus  should  be  very  ex- 
pensive, but  each  article  should  be  good  of  its  kind.  The 
quantity  you  will  require  will  depend  on  the  branch  to 
which  you  devote  yourself.  A  set  for  producing  the  usual 
sized  Glass  Positives  will  require  the  fewest  articles.  For 
the  production  of  Negatives  and  Printing  them  on  paper — 
a  much  higher  branch  of  the  art — more  apparatus  will  be 
necessary.  Should  you  wish  to  be  equally  well  furnished 
for  producing  Portraits  and  Landscapes,  a  full  equipment 
will  be  necessary.  The  following  comprises  a  complete 
set,  equally  adapted  for  all  purposes,  together  with  a  list 
of  Chemicals,  the  quantities  being  calculated  for  the  8|  by 
6  J  inches,  or  "  whole-plate 93  size.  Should  there  be  more 
articles  enumerated  than  you  think  you  will  require,  you 
must  consult  with  some  photographic  friend,  or  explain  to 
the  person  of  whom  you  make  your  purchase,  the  descrip- 
tion and  size  of  pictures  you  wish  to  take,  and  you  will  be 
advised  what  articles  to  omit. 

Apparatus. 

A  Lens  for  Landscape  and  Architecture. 
A  well-made  Bellows  Camera-Box  for  Views. 
A  light,  strong,  but  portable  Tripod  Stand  for  ditto. 

3 


APPABATUS  AND  CHEMICALS  NECESSAKY. 


A  traveling  Glass  Bath  with  water-tight  top. 

A  portable  Dark  Tent,  for  working  in  the  open  air. 

A  good  Portrait  Lens,  fitted  for  a  set  of  Polished  Black 
Glass  Diaphragms. 

A  substantial  square  Camera-Box  for  in-door  work. 

A  strong,  well-made  Camera-Stand  for  in-door  work. 

A  Jenny  Lind  Head-Rest  for  attachment  to  Chair-Backs. 

A  strong  Iron  ditto  for  Standing  Figures. 

Three  Plate  Boxes,  24  grooves,  to  suit  the  sizes  of  the 
Camera. 

Chance's  Sheet  Glass  to  fill  the  above. 

Set  of  Scales  and  "Weights,  with  Pans. 

1  Plate-cleaning  Vice. 

1  or  more  Printing-Frames. 

1  Pneumatic  Plateholder  for  large  Plates. 

1  Developing-Stand  for  ditto. 

2  or  more  Photographic  Ware  or  Porcelain  Dishes. 
1  ditto,  to  be  used  for  Hyposulphite  of  Soda  only. 
1  large  and  1  small  Glass  Funnel. 

1  Gutta-percha  Funnel,  medium  size. 
1  each  20  oz.,  5  oz.,  2  oz.,  and  60  minim,  Graduated 
Glass  Measure. 

1  Four  oz.  tall  Graduated  Collodion  Bottle. 
1  Diamond  for  cutting  Glass  Plates. 
1  Horn  and  1  Boxwood  Pincers. 

1  Hydrometer,  for  testing  the  Strength  of  Silver  So« 
lutions. 

A  few  Glass  Stirring  Bods. 

1  yard  of  Canton  Flannel. 

A  few  wide  and  narrow-mouthed  Bottles. 

A  black  velvet  Focusing  Cloth,  about  one  yard- square. 

Chemicals. 

1  lb.  Bromo-iodized  Negative  Collodion. 
1  lb.  Positive  Collodion. 
5  oz.  Becrystalized  Nitrate  of  Silver. 
1  oz.  Pyrogallic  Acid. 
1  oz.  Citric  Acid. 
1  lb.  Protosulphate  of  Iron. 
1  lb.  Hyposulphite  of  Soda. 
15  gr.  Chloride  of  Gold. 
4  oz.  Kaolin. 

4  oz.  Cyanide  of  Potassium. 

5  oz.  Glacial  Acetic  Acid. 

4 


HOW  TO  1'REPARE  THE  DARK-ROOM. 


5  oz.  Alcohol. 

1  bottle  Varnisn. 

4  oz.  Acetate  of  Soda. 

1  oz.  Bicarbonate  ditto. 

1  bottle  Rotten  Stone. 

1  quire  Album enized  Paper. 

1  ditto  white  Blotting  Paper. 

3  sheets  Litmus  Paper. 

1  packet  of  large  round  Filter  Papers. 

1  ditto  small 

It  is  not  necessary  that  you  should  get  the  chemicals  in 
exactly  the  quantities  given  above,  and  for  sizes  belowr  8^ 
by  6^  in.  smaller  portions  will  do;  yet  it  is  not  well  to  be- 
gin with  too  small  a  stock,  as  from  your  inexperience  you 
will  be  very  apt  to  spill  and  waste  a  quantity  at  first;  and 
if  you  reside  in  a  country  district  you  may  experience  a 
difficulty  in  obtaining  articles  sufficiently  pure  for  your 
use.  As  a  rule,  it  is  better  to  buy  them  of  stock  dealers 
who  supply  photographic  materials,  from  whom  you  will 
obtain  them  cheaper  and  better  than  from  local  chemists 
and  druggists. 

HOW  TO   PREPARE  THE  DARK-ROOM. 

Having  selected  your  Apparatus  and  Chemicals,  the  next 
thing  is  to  prepare  a  room  in  which  to  conduct  your  prin- 
cipal operations.  This  is  technically  called  a  dark-room, 
though,  except  in  a  chemical  sense,  there  is  no  reason  that 
it  should  be  very  dark. 

Many  persons  imagine  that  any  cupboard,  or  out  of  the 
way  corner,  will  do  to  prepare  plates  in :  this  is  a  mistake, 
and  if  you  can  select  a  room  sufficiently  large  in  which 
you  can  move  about  freely,  it  will  be  much  better  than 
being  cooped  up  and  crippled  in  your  actions.  Moreover, 
in  warm  weather,  the  fumes  from  the  chemicals  will  be 
injurious  to  your  health,  if  the  chamber  be  too  small  and 
ill-ventilated.  Everything  that  can  be  spared  should  be 
removed  from  the  room,  and  nothing  allowed  to  remain 
that  can  be  injured  by  chemicals  being  spilt  upon.  It 
should  be  kept  very  clean,  for  dust  and  dirt  are  too  great 
enemies  to  good  photography.  Oilcloth  or  bare  boards 
are  best  for  the  floor,  not  carpet.  A  convenient  range  of 
shelves  should  be  made  round  the  room,  and  some  hooks 
provided  for  hanging  cloths  and  towels  on. 

5 


HOW  TO   BEGIN  WORK. 


You  will  remember  we  explained  that  the  Actinic  force 
that  accompanies  Light  resides  mainly  in  the  blue,  and 
scarcely  at  all  in  the  yellow  rays;  and  photographers  in- 
geniously take  advantage  of  this  fact  by  illuminating  their 
"  dark"  rooms  with  this  non-photographic  light,  and  thus 
see  how  to  prepare  their  most  sensitive  plates.  Every  aper- 
ture and  chink  that  admits  white  light  must  be  carefully 
stopped  up. 

If  there  be  more  windows  than  one,  they  must  be  blocked 
out,  and  the  remaining  one  covered  with  three  folds  of 
yellow  calico;  or,  better  still,  have  a  hinged  frame  to  cover 
the  window,  and  glaze  this  frame  with  dark  yellow  or 
orange  glass,  so  that  you  can  have  yellow  or  white  light  in 
your  room  at  will.  If  a  window  is  not  obtainable,  a  gas 
light,  a  lamp,  or  even  a  candle  may  be  used,  if  a  yellow 
glass  be  provided.  An  ordinary  lamp,  with  a  yellow  paper 
screen  over  it,  makes  a  fair  light  for  the  dark-room.  Per- 
sons usually  make  the  room  for  preparing  their  plates  too 
dark.  This  is  a  mistake;  at  least  sufficient  light  should 
be  admitted  to  enable  you  to  see  what  you  do,  but  it  is  im- 
portant that  this  light  be  quite  yellow.  Should  you  com- 
mit the  error  of  admitting  too  much  light,  you  will  find, 
fully  illustrated,  under  the  head  of  "  Failures,  their  Origin 
and  Remedies,"  near  the  end  of  the  book,  the  proper 
method  of  proceeding. 

Near  the  window  or  lamp,  a  strong  shelf  or  table  should 
be  placed,  on  which  to  place  the  bottles  which  you  will  re- 
quire ;  and  close  at  hand  you  must  have  a  supply  of  water. 
If  you  can  have  the  water  laid  on,  with  regular  tap  and 
sink,  your  arrangements  will  be  perfect;  failing  this,  you 
may  have  a  cask  or  other  vessel  with  a  tap  in  it,  filling  it 
up  with  water  as  you  need;  or,  on  an  emergency,  use  a  jug, 
and  a  pail  to  receive  your  slops.  Have  a  towel  and  soap 
conveniently  placed  to  wash  your  hands  with. 

HOW  TO  BEGIN  WORK. 

Tour  room  being  prepared,  you  are  ready  to  make  a 
commencement,  and  your  natural  desire  will  doubtless  be 
to  take  a  portrait. 

But  as  you  are  a  beginner,  you  should  commence  with 
the  easiest  thing,  and  to  take  a  good  portrait  is  one  of  the 
most  difficult  things  in  photography.  The  proper  pro- 
ceeding is  to  set  up  a  plaster  cast,  engraving,  porcelain 
statuette,  or  similar  still-life  object,  and  practice  upon  it, 

6 


HOW  TO  BEGIN  WORK. 


being  prepared  for  many  failures  arising  from  your  igno- 
rance and  clumsiness,  before  you  attempt  portraiture. 
You  should  try  picture  after  picture,  noticing  carefully 
the  faults  you  commit  in  one,  so  as  to  avoid  them  in  the 
next. 

In  this  way,  by  patience,  observation  and  practice,  you 
will  speedily  gain  such  experience  as  will  make  your  new 
occupation  a  pleasure.  Above  all  things,  do  not  expect  to 
produce  good  pictures  all  at  once;  and  be  not  discouraged 
with  failures,  but  try  to  understand  why  you  fail. 

In  setting  up  an  inanimate  object  to  copy,  the  risks  of 
failure  are  less  than  when  you  have  a  person  to  sit,  for  it 
will  not  move  or  alter  its  expression,  or  make  remarks  if 
you  do  not  succeed.  "When  brother  Tom,  or  friend  Harry 
is  called  in,  the  case  will  be  different;  they  will  be  full  of 
fun  and  jokes,  will  most  likely  move  at  the  critical  mo- 
ment, and  say  disparaging  things  when  they  find  the  pic- 
ture a  failure.  All  this  will  confuse  you,  and  cause  you  to 
omit  things  you  ought  to  have  done,  and  do  abundance  of 
things  you  ought  not  to  have  done,  and  dishearten  you  in 
your  early  progress. 

You  had  better,  therefore,  set  up  a  plaster  cast  bust — 
one  painted  stone-color  will  be  best — such  as  those  of 
Shakspeare,  which  are  so  abundant,  and,  using  this  as  a 
model,  work  frequently  at  it  until  you  have  sufficient  mas- 
tery of  your  instrument  and  materials  to  produce,  with 
moderate  certainty,  a  passably  good  picture;  then  you  may 
proceed  to  portraiture. 

Place  your  object  in  good  light;  a  glass-house  built  for 
the  purpose  is  the  best;  but  this  you  may  not  at  present 
be  able  to  obtain.  A  well-lighted  apartment  will  do,  if  you 
use  a  white  screen — a  sheet  thrown  over  a  clothe's  horse 
— to  reflect  light  upon  the  shaded  side.  A  background 
may  be  formed  by  hanging  some  quiet  drapery  a  little  dis- 
tance behind  your  object. 

Now  get  out  your  portrait  lens,  and  after  wiping  carefully 
the  surfaces  of  the  glasses  with  a  clean  silk  handkerchief 
or  chamois  leather,  screw  it  on  to  your  portrait  camera, 
and  place  them  both  on  your  heavy  camera-stand  opposite 
to  your  object.  The  ground-glass  of  your  camera  should 
have  the  sizes  of  the  glass  plates  marked  on  it  in  squares, 
corresponding  to  the  holders  in  your  dark  slide.  Place 
your  stand  and  camera  so  that  the  lens  is  opposite  to  about 
the  center  of  your  object,  and  move  the  stand  and  camera 
backward  or  forward  until  the  image  of  the  bust  is  of  the 

7 


HOW  TO  TAKE  GLASS  POSITIVES. 


size,  and  occupies  the  place  on  your  ground-glass  that  you 
wish  the  image  to  do  on  the  plate  you  are  going  to  use, 
remarking  that  the  nearer  the  camera  is  to  the  object,  the 
larger  the  object  will  be,  and  vice  versa.  Lay  the  focusing- 
cloth  on  the  camera;  put  your  head  under  the  cloth,  and 
you  will  more  clearly  see  the  image  on  the  ground-glass. 
Slide  in  or  out  the  inner  body  of  the  camera  until  the 
image  is  seen  quite  distinctly,  then  fix  the  camera  with  the 
screw  provided.  While  your  head  is  still  under  the  focus- 
ing-cloth,  pass  your  hand  round  to  the  lens,  and  move 
the  rack  backward  and  forward  till  you  find  the  point  at 
which  it  is  most  distinct.  It  is  then  said  to  be  "in  focus/' 
or  "  sharp."  These  instructions  for  adjusting  the  focus 
apply  to  the  common  camera.  The  best  kind  of  camera  is 
provided  with  an  endless  screw  arrangement,  or  a  rack 
and  pinion,  by  which  the  adjustment  is  made  more  easily 
and  perfectly. 

You  may  now  return  to  your  dark-room,  and  prepare 
your  chemicals  for  "  Glass  Positives/'  these  being  the  most 
easily  produced  photographs. 

HOW  TO  TAKE  GLASS  POSITIVES. 

The  chemicals  required  are — 

Positive  Collodion. 
Nitrate  of  Silver  solution. 
Developing  " 
Fixing  " 
Crystal  Varnish. 
Rotten  Stone. 
Black  Glass. 

The  positive  collodion  you  will  purchase  ready  prepared. 
When  required  for  use,  pour  three  or  four  ounces  into  the 
tall  collodion  bottle;  and  when  you  have  done  for  the  day, 
return  what  remains  back  into  the  stock-bottle,  that  it 
may  settle.  In  this  manner  you  can  always  use  from  a 
clear  quantity,  and  avoid  these  spots  and  defects  which 
arise  from  a  turbid  or  unsettled  collodion. 

The  nitrate  of  silver  solution  is  one  of  the  highest  im- 
portance. To  know  how  much  solution  to  mix,  fill  your 
bath  with  water  to  within  an  inch  of  the  top,  and  measure 

8 


HOW  TO   TAKE  GLASS  POSITIVES. 


how  much  it  holds.  Suppose  it  to  contain  25  fluid  ounces;* 
as  35  grains  of  nitrate  of  silver  to  one  fluid  ounce  of  dis- 
tilled water  is  the  proper  strength,  2  ounces  of  the  nitrate 
will  be  required  to  form  25  fluid  ounces  of  the  necessary 
solution.  Dissolve  the  silver  in  4  ounces  of  distilled  water, 
or  boiled  rain-water,  then  add  a  quarter  of  an  ounce  of 
positive  collodion  to  it,  shake  it  well  for  a  few  minutes, 
and  add  21  ounces  more  of  distilled  water. 

The  solution  will  now  be  a  pale  milky  color,  and  will  re- 
quire filtering.  Should  it  not  run  through  quite  clear,  it 
must  be  re-filtered.  Add  one  drop  of  pure  nitric  acid  to 
every  3  ounces  of  nitrate  solution,  and  then  it  will  be  ready 
for  use. 

Developing  Solution. 

Protosulphate  of  iron  -  100  grains. 

Glacial  acetic  acid       -  \  ounce. 

Water         -----  10  ounces. 

Nitric  acid  -----  5  minims. 

Alcohol       -----  i  ounce. 

Dissolve  the  crystals,  and  if  the  solution  be .  not  quite 
clear,  filter  it,  then  add  the  alcohol  and  acids.  It  will 
keep  good  until  it  is  a  deep  brown  color,  when  it  ought  to 
be  rejected. 

Fixing  Solution. 

Cyanide  of  potassium  60  grains. 

Water         -----       6  ounces. 
Dissolve,  and  it  is  ready  for  use. 

Let  each  of  these  solutions  be  distinctly  labeled,  and 
cork  the  bottles  when  they  are  out  of  use.  The  fixing  so- 
lution had  better  be  marked  "  Poison,"  to  prevent  any  ac- 
cidents. It  should  also  be  particularly  kept  out  of  reach 
of  children,  as  it  is  a  most  deadly  poison,  despite  its  rather 
attractive  smell. 

*  It  is  important  to  notice  that  in  all  photographic  formulae,  where  ounces  of 
fluid  are  named,  fluid  ounces  are  meant,  and  that  the  glass  measures  are  gradu- 
ated for  the  purpose.  When  solids  are  named,  Apothecaries'  weight  is  meant. 
But  the  materials  are  sold  to  you  by  Avoirdupois  weight ;  and  as  the  ounce  of 
the  latter  is  not  so  heavy  as  that  of  the  former,  this  fact  must  be  carefully  re- 
membered, or  disputes  with  shopkeepers,  and  errors  in  mixing  your  solutions, 
will  arise.  The  Apothecaries'  ounce  weighs  480  grains,  and  the  ounce  Avoir- 
dupois but  437£  grains.  It  is  better,  therefore,  in  mixing  nitrate  of  silver  solu- 
tions, to  estimate  the  quantity  required  in  grains,  remembering  that  the  pur- 
chased ounce  of  nitrate  of  silver  will  never  contain  more  than  437£. 

9 


HOW  TO  TAKE  GLASS  POSITIVES. 


How  to  Clean  the  Glass. 

Certain  fixed  sizes  are  used  by  photographers,  and  the 
glasses  are  sold  cut  ready  for  use. 

The  description  of  glass  known  as  "  Polished  Black 
Glass  "  is  well  suited  for  positives,  but,  before  using,  it  re- 
quires careful  cleaning.  The  sharp  edges  should  be  first 
removed  with  a  fine  file,  or  by  drawing  the  edge  of  one 
piece  over  the  edge  of  another;  then  lay  the  glass  on  a 
clean  flat  surface,  or  put  it  in  a  vice,  and  dust  a  little  of 
the  prepared  rotten  stone  in  the  middle.  Rub  it  carefully 
over  every  part  with  a  bit  of  clean  soft  rag:  turn  the  glass 
over,  and  do  the  other  side  the  same.  Then  polish  each  side 
with  a  clean  cloth,  and  finish  with  a  soft  chamois  leather 
kept  expressly  for  this  purpose.  Now  breathe  on  the 
glass;  and  if  the  breath  deposits  evenly,  the  plate  is  clean. 
If  the  plate,  however,  shows  patches  and  marks,  it  must 
be  re-cleaned.  Let  the  edges  be  carefully  wiped,  and  the 
plate  is  ready  for  use.  This  amount  of  cleaning  will  gen- 
erally be  sufficient  for  new  glasses,  but  when  they  have 
been  used  they  require  more  labor.  They  must  then  be 
well  washed  under  the  tap,  to  get  rid  of  all  collodion  and 
chemicals,  and  be  wiped  on  cloths  kept  expressly  for  the 
purpose.  No  soap,  only  plain  soda  and  water,  must  be 
used  in  washing  these  cloths.  Should  the  plates  have  been 
varnished,  they  must  be  soaked  for  some  hours  in  a  satu- 
rated solution  of  washing  soda,  till  the  varnish  and  film 
come  freely  off.  The  glasses  must  then  be  well  washed, 
and  treated  as  already  described.  It  is  a  good  plan,  when 
working,  to  have  a  dish  of  water  at  hand,  and  to  place  the 
spoilt  pictures  in  it  at  once  while  they  are  wet,  and  at  the 
end  of  the  day  to  wash  them  all,  and  put  them  away  clean. 
By  thus  not  allowing  the  films  to  dry  on  the  glasses,  they 
are  much  easier  cleaned,  and  fewer  failures  will  arise  from 
dirty  glasses. 

Collodion  is  a  good  material  for  cleaning  glasses  when 
they  are  not  very  dirty.  Pour  a  few  drops  on  the  glass, 
and  well  rub  it  with  a  clean  cloth,  and  you  will  entirely  re- 
move ali  grease.  A  hint  may  thus  be  taken  how  to  use  up 
waste  collodion. 

Pouring  on  the  Collodion. 

Remove  the  stopper  from  the  bottle,  and  wipe  from  the 
lip  any  dust  or  dry  film  adhering;  and,  holding  the  plate 
horizontally  by  one  corner  with  the  thumb  and  finger  of 
the  left  hand,  pour  steadily  into  the  middle  of  the  plate  as 

10 


HOW  TO  TAKE  GLASS  POSITIVES. 


much  collodion  as  will  half  cover  it.  Then  gradually  in- 
cline the  plate  so  that  the  collodion  flows  to  each  corner, 
not  allowing  it  quite  to  touch  the  thumb,  nor  to  flow  a 
second  time  to  any  part;  then  steadily  pour  back  the  ex- 
cess from  one  corner  into  the  bottle,  and  while  the  plate 
rests  on  the  mouth  of  the  bottle,  move  the  plate  backward 
and  forward  to  prevent  the  collodion  setting  in  crapy  lines. 
Perform  this  operation  coolly  and  steadily,  and  try  to  avoid 
spilling  any  of  the  collodion.  A  little  practice  will  make  it 
easy.  When  the  collodion  is  set — usually  in  a  few  seconds 
- — the  plate  is  ready  to  be  immersed  in  the  nitrate  of  silver 
bath.  Lift  the  dipper  up,  and  place  the  back  of  your 
plate  on  it — it  will  adhere  by  capillary  attraction — and  im- 
merse plate  and  dipper  into  the  bath  solution  with  one 
steady  dip,  and  continue  to  agitate  the  plate  by  moving  it 
about  in  the  bath  for  a  few  seconds.  Take  care  it  does  not 
slip  off  the  dipper.  After  agitating  the  plate,  cover  it  over 
to  keep  it  from  light  and  dust.  If  there  be  the  least  hesi- 
tation or  stop  while  the  plate  is  being  immersed,  there  will 
be  a  line  marked  across  the  plate.  To  know  how  long  to 
keep  the  plate  before  putting  it  in  the  bath,  after  it  is  collo- 
dionized,  is  a  point  that  you  will  gain  by  experience;  but 
it  depends  on  many  circumstances,  such  as  the  nature  of 
the  collodion  and  the  temperature ;  but  this  rule  will  guide 
you;  if  you  put  the  plate  in  too  soon,  streaks  and  marks 
will  be  formed,  commencing  from  where  it  first  touched 
the  silver  solution.  If  you  do  not  immerse  it  soon  enough, 
the  part  of  the  plate  that  has  become  too  dry  will  be  in- 
sensitive, and  will  show  a  transparent  mark.  By  noticing 
these  points,  you  can  judge  whether  you  have  made  an  er- 
ror in  the  time  of  immersion.  The  plate  must  remain  in 
the  bath  in  summer  time  about  two  minutes,  and  in  winter 
from  five  to  ten. 

"While  the  plate  is  in  the  bath,  you  must  get  ready  your 
dark  slide,  and  see  that  there  is  no  dirt  in  it.  When  ready 
to  put  your  plate  in  the  bath,  you  must  shut  your  door, 
and  see  that  only  yellow  light  illuminates  the  room.  Lift 
the  plate  up  and  down  in  the  bath  several  times  by  means 
of  the  dipper,  and  the  agitation  of  the  solution  will  re 
move  the  oily-looking  lines  on  the  surface.  Allow  it  to  re- 
main in  the  bath  till  all  apparent  greasiness  is  removed, 
and  the  film  has  become  creamy-looking.  Then  take  it 
off  the  dipper,  and,  handling  it  as  carefully  as  possible — 
chiefly  by  the  corner  uncollodionized — let  it  drain  for  a 
few  seconds  on  clean  blotting-paper,  and  then  lay  it,  collo- 

11 


HOW  TO  TAKE  GLASS  POSITIVES. 


dion  side  downward,  into  your  dark  slide,  the  silver  wire 
corners  supporting  it  by  the  four  corners.  Close  up  your 
dark  slide,  and  your  plate  is  ready  for  use. 

You  may  now  return  to  your  plaster  cast,  and  removing 
the  ground-glass  frame  from  the  camera,  insert  the  dark 
slide  in  the  place.  Cover  the  lens  with  the  cap,  raise  the 
shutter  of  the  dark  slide,  and  gently  remove  the  lens  cap, 
so  as  not  to  shake  the  camera :  thus  the  light  will  be  ad- 
mitted to  the  sensitive  plate.  Experience  can  alone  deter- 
mine the  length  of  the  "  exposure."  The  brilliancy  of  the 
light,  color  of  object,  kind  of  lens,  nature  of  collodion,  time 
of  day,  and  even  the  period  of  the  year,  are  all  modifying 
circumstances. 

Suppose  you  allow  ten  seconds.  Count  the  time  ex- 
actly, and  replace  the  cap  on  the  lens.  Next  shut  down 
the  shutter  of  the  slide,  and  take  it  into  the  dark-room. 
Close  the  door,  and  noticing  that  no  white  light  is  admitted, 
remove  the  plate  carefully  from  the  dark  slide.  The  ni- 
trate solution  that  has  accumulated  at  the  bottom  drain 
off  with  clean  blotting-paper.  Put  about  an  ounce  of  de- 
veloping solution  into  a  clean  measure  glass,  and  holding 
the  plate  horizontally  by  the  bare  corner,  collodion  side 
upward,  pour  steadily  but  quickly  along  the  bottom  edge 
of  the  plate  sufficient  to  easily  cover  it;  gently  incline  the 
plate  to  allow  the  developing  solution  to  flow  uniformly 
backward  and  forward.  Watch  the  "coming  out"  of  the 
image.  The  image  will  quickly  appear;  first  the  parts 
most  strongly  lighted  will  show  themselves,  next  the 
shaded  portions,  and  when  these  are  fully  out,  turn  off  the 
solution,  and  wash  the  plate  well,  by  allowing  the  water 
from  the  tap  to  flow  over  it  for  not  less  than  one  minute, 
or  until  all  the  greasy  lines  disappear. 

Lay  the  plate  in  a  shallow  photographic  ware  or  porce- 
lain dish  kept  for  the  purpose,  and  quickly  pour  over  it 
sufficient  of  the  fixing  solution  to  cover  it.  Directly  the 
yellow  film  of  iodide  of  silver  is  dissolved,  the  plate  must 
be  lifted  out  and  well  washed.  When  the  plate  goes  into 
the  fixing  solution,  white  light  may  freely  be  admitted. 
The  fixing  solution  must  be  put  back  into  its  bottle,  and  may 
be  used  as  long  as  it  continues  to  dissolve  the  yellow  film. 

If  the  exposure  be  correct,  and  you  have  developed 
properly,  you  will  now  have  a  nice  picture  of  your  bust.* 

*  If  the  picture  be  not  perfect,  refer  to  the  chapter  on  "  Failures,  their  Ori- 
gin and  Remedies  "  for  further  instructions. 

12 


HOW  TO  TAKE  NEGATIVES. 


Tour  plate  may  be  dried  spontaneously  or  by  heat.  The 
collodion  surface  now  requires  varnishing,  to  protect  it 
from  atmospheric  action.  Remove  carefully  with  a  camel's 
hair  brush  any  dust  or  dirt  on  the  picture,  and  pour  the 
varnish  over  it  as  you  did  the  collodion.  Drain  it,  and  when 
dry  your  picture  is  finished,  and  ready  to  be  mounted. 

You  have  now  passed  through  the  various  operations, 
and  it  only  requires  practice  and  observation  to  make 
them  familiar  to  you.  Having  obtained  this  practice,  the 
bust  may  be  removed,  and  a  friend  being  placed  in  its 
stead,  you  may,  by  applying  the  same  manipulations,  pro- 
duce a  portrait.  Let  him  sit  in  an  easy,  graceful  position, 
and,  if  necessary,  steady  his  head  by  the  use  of  the  head- 
rest. Let  him  look  at  some  dark  object,  and  allow  him  to 
wink  his  eyes  freely  during  the  sitting,  but  caution  him  to 
be  quite  steady  in  all  other  respects. 

HOW  TO  TAKE  NEGATIVES. 

The  pictures  produced  by  the  above  method  have  the 
disadvantage  that  a  separate  sitting  is  required  for  every- 
one; this,  together  with  the  fragility  of  the  material,  has 
caused  the  process  to  be  less  generally  followed  than  the 
more  complex  one,  where  a  negative  is  first  obtained,  from 
which  an  indefinite  number  of  paper  pictures  can  be  pro- 
duced. The  practice,  however,  you  acquire  in  producing 
glass  positives  will  be  extremely  useful  in  producing  nega- 
tives, as,  up  to  a  certain  point,  the  manipulations  are 
similar. 

You  must  clearly  understand  the  difference  between  a 
Negative  and  a  Glass  Positive.  Every  glass  picture,  to  a 
certain  extent,  partakes  of  the  nature  of  both;  but  a  "glass 
positive  "  is  a  picture  done  at  one  operation,  and  complete 
in  itself;  whilst  a  Negative  is  not  so  much  a  picture  as  the 
means  of  producing  one. 

Glass  positives  are  examined  by  reflected,  negatives  by 
transmitted,  light;  the  one  you  hold  down  to  look  at,  the 
other  you  hold  up  to  look  through;  the  former  are  black 
varnished  to  make  them  opaque,  if  not  taken  on  black 
glass;  the  latter  clear  varnished  to  give  transparency.  The 
one  shows  natural  objects  as  they  are — lights  for  lights 
and  darks  for  darks;  the  other,  just  the  reverse — faces, 
hands,  and  linen  very  dark,  and  black  drapery  quite  clear. 
Hold  a  picture  of  each  kind  up  to  the  light  and  look 
through  them,  the  positive  will  appear  thin  and  transpar- 


HOW  TO  TAKE  NEGATIVES. 


ent,  the  negative  dense  and  opaque;  turn  them  down  and 
look  at  them,  the  positive  is  clear  and  distinct,  the  nega- 
tive misty  and  confused.  The  two  kind  of  pictures  are  so 
different  that  you  must  judge  each  by  its  own  rules;  for 
what  is  a  fault  in  one,  may  be  a  merit  in  the  other.  In 
other  wrords,  a  negative  is  a  glass  picture  produced  by 
somewhat  similar  means  to  a  positive,  only  that  in  the  de- 
velopment a  much  thicker  and  denser  deposit  is  formed. 

In  fact,  the  negative  is  to  the  photographer  what  the 
types  are  to  the  printer;  and  as  the  latter,  you  know,  are 
arranged  just  contrary  of  the  impression  that  is  taken  from 
them,  so  must  the  photographer's  negatives — his  types — 
be  the  reverse  of  his  prints.  The  analogy  between  the  two 
processes  is  so  considerable,* that  the  production  of  paper 
pictures  by  the  aid  of  negatives  is  always  termed  printing. 

It  will  be  a  great  assistance  to  you,  if  you  can  obtain 
from  some  photographer  a  negative  that  you  can  keep  by 
you,  to  compare  with  your  own,  until  you  have  acquired 
experience  to  know  how  to  judge  for  yourself. 

The  same  apparatus  serves  for  the  production  of  nega- 
tives as  positives,  but  some  of  the  chemicals  are  different; 
those  that  you  require  are — 

Bromo-iodized  negative  collodion. 
Nitrate  of  silver  bath  solution. 
Developing  " 
Fixing  " 
Spirit  varnish, 

The  Bromo-iodized  Negative  Collodion  is  rather  differ- 
ent in  its  preparation  to  positive  collodion,  and  is  better 
adapted  for  giving  dense  pictures.  It  is  often  supplied  as 
plain  collodion  and  iodizing  solution.  It  is  made  ready 
for  use  by  mixing  three  parts  by  measure  of  the  former  to 
one  of  the  latter.  It  is  better  to  mix  it  a  few  hours  before 
using,  so  that  time  be  allowed  for  floating  particles  to 
subside. 

Nitrate  of  Silver  Bath  Solution. 
The  same  you  used  for  positives  will  not  do  for  negatives. 

Eecrystalized  nitrate  of  silver  2  ounces. 

Distilled  or  boiled  rain-water  -      -    25  " 

Dissolve  the  silver  in  four  ounces  of  the  water;  dissolve 

14 


HOW  TO  TAKE  NEGATIVES. 


two  grains  of  iodide  of  potassium  in  one  ounce  of  the 
water,  and  add  it  to  the  four  ounces  of  silver  solution; 
agitate  till  the  yellow  precipitate  formed  first  is  dissolved. 
Add  a  few  drops  of  a  saturated  solution  of  bicarbonate  of 
soda,  agitating  well  between  each  addition,  until  the  silver 
solution  becomes  rather  milky,  then  add  the  remaining  20 
ounces  of  distilled  water.  Filter,  and  add  half  a  drachm 
of  glacial  acetic  acid,  and  your  nitrate  bath  is  ready  for 
use.  Eill  it  up  from  time  to  time  with  a  plain  solution  of 
nitrate  of  silver,  50  grains  to  the  ounce. 

Developing  Solution  for  Negatives. 

Protosulphate  of  iron  -  150  grains. 

Glacial  acetic  acid  -  \  ounce. 

Alcohol  -      -       -  -  1  « 

Distilled  water  10 

This  solution  gradually  acquires  a  sherry  color,  but  its 
quality  remains  equally  good.  It  should  be  filtered  before 
using. 

Fixing  Solution. 

Hyposulphite  of  soda  5  ounces. 

Water    -  5 

This  solution  may  be  used  until  it  loses  its  power  of 
fixing  the  negative.  It  soon  becomes  discolored,  but  that 
is  of  no  consequence. 

Chance's  Sheet  or  B.  P.  C.  is  good  glass  for  negatives, 
as  Crown  is  not  flat  enough.  It  requires  the  same  careful 
cleaning  as  for  positives.  As  it  is  more  difficult  to  produce 
clean  negatives  than  positives,  you  had  better  accustom 
yourself  to  use  a  glass  one  size  larger  than  you  require,  so 
that  the  defects,  which  usually  occur  on  the  margin  of  the 
plate,  may  not  spoil  your  picture. 

Pour  the  collodion  on  the  plate,  sensitize,  drain,  and 
place  it  in  the  dark  slide  carefully,  and  according  to  the 
directions  given  for  glass  positives. 

The  same  difficulty  occurs  with  negatives,  in  giving  any 
rule  for  the  length  of  exposure,  as  in  positives;  the  ap- 
pearance of  the  plate  during  development  is  a  useful  guide, 
but  they  always  require  at  least  twice  as  long  time  as  for 
positives.  Be  very  careful,  when  your  plate  is  in  the  dark 
slide,  to  keep  it  erect,  and  to  handle  it  gently.  Never 

15 


HOW  TO  TAKE  NEGATIVES. 


knock  it  against  anything,  or  it  will  be  covered  with  abund- 
ance of  spots  from  particles  of  dust  and  dirt  falling  on  it. 
When  in  the  dark-room,  take  the  plate  out  as  carefully  as 
before,  and  remove,  with  clean  blotting-paper,  the  nitrate 
solution  that  has  accumulated  at  the  bottom;  and  holding 
it  by  the  corner,  pour  over  it  the  developing  solution,  and 
in  a  few  seconds  the  image  will  appear.  After  a  little  ex- 
perience you  will  be  able  to  judge,  by  the  manner  in  which 
the  image  makes  its  appearance,  whether  you  have  given 
the  proper  exposure  in  the  camera. 

If  it  start  out  at  once,  directly  the  developer  has  flowed 
over  the  plate,  the  exposure  has  been  too  long;  but  if  the 
image  comes  out  slowly  and  reluctantly,  and  you  have 
difficulty  in  making  the  deepest  shades  appear,  it  has  not 
been  exposed  long  enough. 

The  happy  medium  between  these  two  is  the  correct 
time.  When  this  has  been  given,  the  image  makes  its  ap- 
pearance steadily  and  gradually — first  the  high  lights,  next 
the  light  shades,  and  finally  the  deep  shadows.  Suppose 
it  a  portrait  of  a  gentleman — the  shirt-front,  face,  and 
hands  are  first  seen;  the  light  folds  of  the  drapery  next 
show  themselves ;  and  lastly,  the  details  in  the  darkest 
parts.  If  it  were  a  positive,  you  would  have  poured  the 
developer  off  before  these  last  were  seen;  but,  being  a 
negative,  you  must  carry  it  on  until  the  whole  of  the  de- 
tails are  clearly  out,  then  pour  the  solution  off  the  plate 
and  wash  it  well.  By  holding  your  plate  up  to  the  light 
and  looking  through  it,  you  will  see  the  image  as  a  nega- 
tive— the  whites  all  dark,  and  dark  portions  nearly  trans- 
parent; and  if  the  picture  appear  in  proper  harmony,  mak- 
ing allowance  for  reversed  effects,  the  lighter  portions 
being  nearly  opaque,  and  the  darker  parts  very  clear — but 
the  whole  picture  full  of  gradations  and  half-tones,  with 
scarcely  any  parts  entirely  opaque,  and  very  few  clear  glass 
— then  the  development  is  complete;  if,  however,  the  pic- 
ture presents  somewhat  this  appearance,  but  is  deficient 
in  opacity  of  deposit,  or  "  density,"  it  must  be  "  intensi- 
fied." To  do  this,  pour  over  the  plate  as  much  as  will 
comfortably  cover  it  of  the  following: 

•    Negative  Intensifying  Solution. 

Pyrogallic  acid  -  3  grains. 

Citric  acid   1  grain. 

Glacial  acetic  acid  J  drachm. 

Distilled  water  -  1  ounce. 

16 


HOW  TO  TAKE  NEGATIVES. 

When  this  solution  has  thoroughly  mixed  with  the  water 
on  the  plate,  pour  it  back  into  the  measure-glass,  and  add 
a  few  drops  of  nitrate  of  silver  solution  to  it  (30  grains  to 
the  ounce  of  water),  mix,  and  pour  again  over  the  plate; 
the  image  will  speedily  begin  to  intensify — that  is,  the 
silver  will  be  deposited  over  the  various  parts  where  the 
light  has  acted.  This  intensifying  must  be  continued  until 
the  parts  of  the  negative  most  lighted  have  the  requisite 
opacity. 

This  solution  sometimes  becomes  turbid  and  muddy  be- 
fore the  picture  is  dense  enough.  In  such  a  case,  pour  it 
away,  and  renew  with  some  fresh  intensifying  solution  and 
silver,  and  proceed  as  before.  This  may  be  repeated  many 
times,  if  needed,  until  the  required  effect  is  produced. 
Here  is,  perhaps,  the  most  difficult  thing  you  have  to  learn 
— to  know  how  far  to  go,  and  wThen  to  stop ;  how  to  gain 
intensity  enough  to  produce  a  vigorous  negative,  and  yet 
to  avoid  making  it  too  dense,  and  losing  half-tone.  As  a 
rule,  beginners  over-develop  their  positives,  and  under- 
develop  their  negatives. 

But  it  is  possible  to  intensify  too  much,  and  make  the 
picture  so  dense  that  you  cannot  print  through  it.  You 
must  watch  the  kind  of  prints  that  different  negatives  pro- 
duce, and  when  you  find  one  that  gives  a  brilliant  yet  soft 
image — for  the  real  test  of  a  negative  is  the  kind  of  print 
it  produces — study  that  negative  well,  observe  the  degree 
of  opacity  it  has,  and,  keeping  it  as  a  standard,  try  and 
produce  all  others  like  it.  In  this  way  you  can  train  and 
educate  yourself  to  produce  good  negatives. 

The  development  and  intensifying  being  finished,  wash 
the  plate  and  lay  it  in  the  dish;  pour  the  fixing  solution 
over,  and  when  the  yellow  iodide  is  dissolved  out,  give  it  a 
careful  and  copious  washing;  for  if  any  of  the  hyposul- 
phite of  soda*  remain  in  the  film,  it  will  crystalize  and 
spoil  it. 

Your  picture  now  being  washed,  you  may  calmly  examine 
it.  If  it  appear  as  a  moderately  good  but  over-exposed 
positive,  with  a  red  and  green  pearly  tint,  and  on  looking 
through  it,  shows-  abundance  of  half-tones,  both  in  the 
opaque  and  transparent  parts,  you  may  consider  you  have 
a  correctly-exposed  and  well-developed  negative,  and  one 
from  which  you  may  anticipate  brilliant  prints. 

If,  however,  the  negative  appear  as  a  good  positive,  with 
brilliant  blacks,  but  rather  chalky  whites,  and  on  looking 
through  if  these  latter  are  very  dense  without  half-tone, 

17 


HOW  TO  VARNISH  THE  NEGATIVE  POSITIVE  PRINTING. 

and  the  former  almost  like  bare  glass,  then  your  picture  is 
defective,  and  will  only  produce  a  hard  black  and  white 
print;  the  fault  being  that  it  was  not  long  enough  exposed 
in  the  camera. 

Should  it,  however,  appear  as  a  very  much  over-exposed 
positive,  the  whole  plate  having  a  gray  film  over  it,  obscur- 
ing the  image,  and  on  looking  through,  the  details  of  the 
shadows  are  almost  as  intense  as  the  white  linen,  and  the 
whole  picture  is  deficient  m  contrast,  then  it  has  been 
over-exposed. 

The  two  instances  we  have  pointed  out  are  extreme 
ones:  it  is  your  object  to  avoid  each;  but  of  the  two  errors, 
under-exposure  is  the  worst,  for  by  careful  printing  you 
may  get  a  passable  proof  from  an  over-exposed  negative ; 
but  no  dexterity  will  avail  with  an  under-exposed  one,  and 
unfortunately,  beginners'  negatives,  from  their  great  desire 
to  "  work  quick,"  have  too  frequently  this  latter  fault. 

HOW  TO  VARNISH  THE  NEGATIVE. 

After  the  plate  has  been  well  washed  and  dried,  it  is 
ready  to  varnish.  If  only  a  few  prints  are  wanted,  and 
you  do  not  intend  to  keep  the  negative,  you  may  use  a 
cheap  varnish.  If,  however,  you  value  your  negative,  and 
purpose  producing  many  prints  from  it,  the  cheap  varnish 
will  not  give  sufficient  protection,  and  you  must  use  a 
spirit  varnish  which  will  produce  a  much  harder  sur- 
face. To  use  this  spirit  varnish,  warm  the  negative 
before  a  fire  uniformly  all  over  as  hot  as  the  back  of  the 
hand  will  bear,  then  pour  the  varnish  on  like  collodion, 
drain  off,  and  dry  it  with  heat.  The  proper  degree  of  heat 
to  use  will  be  acquired  by  a  little  experience  ;  if  the  plate 
be  made  too  hot,  the  varnish  will  not  flow  uniformly  over, 
but  will  run  and  dry  into  irregular  streaks.  If  it  be  not  hot 
enough,  the  surface  will  dry  dull  and  dead.  With  the  me- 
dium heat  the  film  will  dry  with  a  hard,  glossy  surface. 
When  cold,  your  negative  is  ready  to  be  printed  from. 

POSITIVE  PRINTING  ON  PLAIN  AND  ALBUMENIZED  PAPER. 

The  learner  having  now  got  his  negative  in  readiness  to 
print  from,  will  find  full  details  of  the  manipulations  of 
the  printing  process  commencing  on  page  192  of  this  book. 


18 


PHOTOGRAPHY. 


CHAPTER  I. 

HISTORY  OF  PHOTOGRAPHY. 

Every  step,  whether  thoughtlessly  or  discreetly  taken,  is 
the  commencement  of  a  new  era  in  a  man's  life.  As  in  a 
game  of  chance — where  either  red  or  black  must  occur  at 
the  cessation  of  motion  in  the  finger  of  the  dial-plate — the 
probability  that  red  will  prevail  over  the  black  the  next 
time,  because  black  has  occurred  for  twenty  times  in  succes- 
sion, is  not  valid  ;  it  is  equally  probable  that  black  will  be 
the  successful  color  ;  so,  in  the  game  of  life,  each  successive 
move  is  a  new  beginning  ;  and,  as  a  single  twirl  of  the  rou- 
lette may  be  the  bane  or  the  boon  of  the  career  of  an  indi- 
vidual, so  the  slightest  event,  the  most  insignificant  indeed, 
may  turn  out  to  be  the- center  of  incalculable  results.  New 
developments  in  the  science  of  nature  are  not  limited  to 
their  own  immediate  sphere  ;  they  act  and  react  upon  the 
past  and  the  future,  by  illustrating  phenomena  that  before 
were  dark  and  not  understood,  or  by  eliciting  truths  which 
hitherto  were  utterly  unknown.  Thus  it  is  that  the  inven- 
tion of  a  machine,  the  improvement  of  a  part  of  a  machine, 
or  the  discoveiy  of  some  new  chemical  ingredient,  may  be 
the  date  of  the  commencement  of  a  new  history.  The  verifi- 
cation of  this  idea  is  pertinently  made  manifest  in  the  change 
from  the  simple  double  convex  lens  to  the  achromatic  com- 
bination by  Dolland  ;*  in  the  change  from  the  signal  tele- 
graph on  the  mountains  to  the  electric  telegraph  in  the 
closet ;  in  the  improved  application  of  steam  by  Watt ;  in 
the  development  of  a  picture  on  the  iodized  plates  of  silver 
by  the  vapor  of  mercury;  and  in  the  discovery  of  the  hypo- 

*  Dolland,  J.,  was  born  in  London,  in  the  year  1706,  and  died  in  1762. 


10 


HISTORY  OF  PHOTOGRAPHY. 


sulphite  of  soda,  cyanide  of  potassium,  pyrogallic  acid,  and 
the  protosalts  of  iron.  For  from  the  moment  that  chro- 
matic and  spherical  aberration  could  be  reduced,  the  tele- 
scope and  the  microscope  became  altogether  new  instru- 
ments in  the  hands  of  the  natural  philosopher,  by  which 
many  crude  notions  were  quickly  laid  aside  as  false,  and 
many  new  truths  as  quickly  denuded  of  their  cloudy  habili- 
ments. Astronomy,  one  of  the  oldest  of  sciences — one  whose 
history  can  be  traced  back  to  the  time  of  the  Chaldeans — 
entered,  at  the  time  of  the  introduction  of  the  achromatic 
refracting  telescope,  upon  an  epoch  as  distinct  in  its  history 
as  the  transition  from  the  system  of  Hipparchus  to  that  of 
Copernicus.  At  the  same  time,  too,  Physiology  received  a 
new  impetus,  by  the  deductions  drawn  with  the  aid  of  the 
compound  achromatic  microscope,  so  that  Biology,  since 
then,  is  gradually  becoming  more  and  more  of  a  science. 
By  means  of  the  former  improved  instrument,  our  eyes  are 
permitted  to  revel  amid  the  enchanting  scenes  of  the  starry 
firmament,  by  the  latter  to  scrutinize  the  realms  of  minute 
organisms  of  the  earth,  and  by  both  to  become  acquainted 
with  the  secrets  of  creation.  For  the  investigator  of  nature 
in  the  great  and  the  minute,  this  is  a  new  era  in  the  history 
of  the  world  as  it  exists  and  acts.  In  like  manner  the  age 
of  steam  and  the  telegraph  commenced  a  new  history  in  the 
social  existence  and  actions  of  men.  The  mild  tenets  of  the 
Gospel,  which  would  seem  to  have  no  connection  whatever 
with  the  subject,  have  been  more  powerfully,  more  effica- 
ciously implanted  in  foreign  soils,  by  the  accessory  instru- 
mentality of  these  agents,  than  by  any  preceding  direct 
operations  of  the  missionary  organization ;  the  superiority 
of  the  race  of  men  that  have  invented  and  that  wield  such 
mighty  instruments  for  weal  and  for  woe,  is  so  distinctly 
marked,  that  admiration  and  awe  have  engendered,  in  the 
minds  of  the  ignorant  and  less  enlightened,  respect  for  the 
creeds  of  religion  and  morality  of  their  superiors.  Co- 
existent with  the  steam-engine  and  the  electric  telegraph, 
and  equally  important  as  these  in  its  influence  on  the  ways 
and  means  of  life,  is  the  art  of  sun-drawing.  It  is  one  of 
the  great  wonders  of  the  phenomena  of  created  matter,  so 
far  eclipsing  the  seven  vaunted  wonders  of  the  world,  that 
these  recede  into  dark  nooks,  like  the  wired  dolls  of  an  au- 
tomatic puppet-show.  This  art,  and  the  science  that  ex- 
plains the  different  effects  produced  in  its  manipulations, 
form  the  subject  of  the  present  volume.  The  art  and  the 
science  are  of  modern  origin  and  of  recent  date. 


HISTORY  OF  PHOTOGRAPHY. 


11 


Sun-drawing,  Heliography,  and  Photography  are  synony- 
mous expressions  for  the  same  phenomenon,  although  ety- 
mologically  the  two  latter  are  somewhat  different — helio- 
graphy signifying  sun-writing,  whilst  the  word  photography 
signifies  light-writing,  Not  one  of  these  exjDressions  is 
strictly  correct,  because  actinic  impressions  can  be  obtained 
from  rays  emanating  from  the  moon,  from  artificial  light,  or 
the  electric  spark.  Actinic  drawing  would  probably  be  the 
best  name,  although  as  regards  the  representation  of  facts 
by  words,  it  is  immaterial  for  the  masses  of  mankind  whether 
these  words  have  an  intrinsic  or  root-meaning  or  not.  The 
phenomena  comprehended  under  any  one  of  the  above  syn- 
onymous expressions,  depend  immediately  upon  what  is 
termed  light  as  the  force  or  cause,  and  upon  the  property, 
which  only  certain  substances  apparently  possess,  of  being 
affected  according  to  the  intensity  of  the  light  employed? 
The  principal  of  these  substances  are  the  salts  of  silver,  the 
salts  of  iron,  bichromate  of  potassa,  and  certain  resins,  as 
the  oil  of  lavender  and  asphaltum.  That  light  acts  upon  or- 
ganized substances  is  a  phenomenon  which  must  have  been 
observed  by  the  first  occupants  of  earth ;  they  could  not 
fail  to  remark  the  brilliant  hues  on  the  side  of  an  apple  that 
received  the  direct  rays  of  the  sun,  and  to  contrast  these 
resplendent  mixtures  of  red,  crimson,  green,  purple,  yellow, 
orange,  and  other  colors,  on  the  one  side,  with  the  white, 
or  greenish  white,  on  the  side  exposed  simply  to  the  diffused 
light  of  day.  The  variegated  foliage  of  a  tropical  clime,  as 
contrasted  with  the  continual  merging  into  green,  according 
to  the  increase  in  latitude,  gives  evidence  of  the  influence 
of  actinic  action ;  and  this  change  of  green  into  white  in 
the  leaves  and  stalks  of  similar  plants,  when  supplied  with 
heat  and  air,  and  not  with  light,  is  a  still  stronger  proof  of 
heliographic  influence.  But  this  species  of  influence  is  not 
limited  to  the  vegetable  part  of  the  earth ;  it  is  perceived, 
in  all  its  beauties,  in  the  blooming  cheeks  of  a  maiden  from 
Kaiserstuhl  in  the  Black  Forest,  or  from  the  pasturing  de- 
clivities of  the  Tyrolese  Alps ;  and  its  deficiency  is  quite  as 
apparent  in  the  pale,  white,  and  lifeless  facial  integuments 
of  the  unfortunate  denizens  of  crowded  cities,  as  in  the 
blanched  stalks  of  celery  in  a  dunghill,  or  the  sickly  white 
filiform  shoots  of  potatoes  in  a  dark  cellar.  These  phenom- 
ena are  full  of  wonder,  no  less  so  than  any  of  the  opera- 
tions of  sun-drawing  on  paper  or  collodion,  and  quite  as  in- 
explicable ;  but  they  have  long  failed  to  excite  astonishment, 
from  the  frequency  and  commonness  of  their  occurrence. 


12 


HISTORY  OF  PHOTOGRAPHY. 


The  first  remark  in  reference  to  the  cause  of  the  change 
of  color  in  silver  salts  is  due  to  the  distinguished  Swedish 
chemist,  Scheele.*  He  regarded  the  blackening  effect  of 
chloride  of  silver,  when  exposed  to  the  rays  of  the  sun,  as 
caused  by  a  species  of  reduction  of  the  salt  to  the  metallic 
state  and  the  accompanying  formation  of  hydrochloric  acid. 
He  undertook  a  course  of  experiments,  to  ascertain  whether 
all  the  colors  of  the  spectrum  had  an  equal  influence  in  col- 
oring or  blackening  this  salt,  and  arrived  at  the  conclusion 
that  the  maximum  chemical  or  decomposing  action  of  the 
spectrum  was  in  the  neighborhood  of  the  violet  part,  and 
that  it  gradually  diminished  toward  the  red,  where  it  was 
scarcely  perceptible.  The  researches  of  Scheele  in  this  track 
terminated  here  ;  and  no  application  of  the  property  of  black- 
ening of  the  chloride  of  silver  to  photogenic  purposes  was 
made  until  after  the  lapse  of  several  years. 

In  1801  Ritterf  not  only  corroborated  the  experiments  of 
Scheele,  but  demonstrated  that  chloride  of  silver  was  black- 
ened to  some  distance  external  to  the  spectrum,  on  the  violet 
side.  The  scientific  investigators  of  the  time  repeated  the 
experiments  without  any  further  developments. 

Dr.  WollastonJ  published  a  report  of  experiments  which 
he  made  with  gum-guaicum,  when  acted  upon  by  the  dif- 
ferent colored  rays  of  the  spectrum.  The  violet  rays  turned 
paper,  stained  yellow  by  a  solution  of  this  gum  in  alcohol, 
to  green,  which  was  soon  changed  back  to  yellow  by  the 
red  rays ;  he  discovered  afterward,  however,  that  the  heat  of 
the  red  rays  was  sufficient  of  itself  to  reproduce  the  yellow 
color  of  the  tincture  of  the  gum. 

The  same  results  were  obtained  by  Berard.  He  experi- 
mented with  half  the  spectrum  at  a  time,  which  was  con- 
densed by  a  lens  to  a  focus,  and  made  to  impinge  at  this 
point  upon  chloride  of  silver.  The  half  next  the  violet,  or 
more  refrangible  rays,  were  very  efficacious  in  discoloring 
this  salt  of  silver ;  wrhilst  the  other  half,  or  red  side,  and 
least  refrangible  rays,  although  far  more  luminous,  produced 
no  blackening  effect.  The  experiments  of  Seebeck  seem 
to  show  that  light  transmitted  through  colored  glass  pro- 

*  Scheele,  Charles  William,  was  born  on  the  nineteenth  of  December, 
1742,  at  Stralsund,  Sweden.  He  died  on  the  twenty-first  of  May,  1786,  at 
Koeping,  on  Lake  Moeler. 

f  Ritter,  John  William,  was  born  at  Samitz,  in  Silesia,  in  1776,  and  died 
in  1810. 

%  Wollaston,  William  Hyde,  M.D.,  was  born  on  the  sixth  of  August, 
1766,  at  East-Dereham,  and  died  December  twenty  second,  1828,  in  London. 


HISTORY  OF  PHOTOGRAPHY. 


13 


duced  the  same  general  effect  as  the  different  colored  rays 
of  the  spectrum.  He  furthermore  ascertained  that  a  piece 
of  paper  dipped  in  a  rather  concentrated  and  neutral  solu- 
tion of  chloride  of  gold,  in  the  dark,  was  not  reduced,  as 
long  as  it  was  kept  in  the  dark;  whereas  if  it  had  previously 
been  exposed  to  the  direct  rays  of  the  sun,  it  gradually 
turned  purple  in  the  dark  chamber.  Sir  Humphry  Davy 
observed  that  the  oxide  of  lead,  in  a  moist  condition,  is  acted 
upon  very  differently  by  the  red  and  the  violet  rays  of  the 
spectrum ;  by  the  latter,  the  puce-colored  oxide  is  turned 
black — by  the  former,  red.  He  ascertained,  too,  that  hy- 
drogen and  chlorine,  when  exposed  to  the  rays  of  the  sun, 
frequently  enter  into  combination  so  vividly  as  to  produce 
an  explosion  in  the  formation  of  hydrochloric  acid  ;  but  the 
two  gases  may  be  kept  in  contact,  in  the  dark,  without  un- 
dergoing much  change.  A  solution  of  chlorine  in  water  re- 
mains unchanged,  as  long  as  it  is  kept  out  of  the  light ;  but 
is  soon  converted  into  hydrochloric  acid,  by  decomposing 
the  water,  when  exposed  to  the  sun.  A  similar  case  of  de- 
composition is  effected  by  light,  when  carbonic  oxide  and 
chlorine  are  exposed  to  light ;  they  then  enter  into  combi- 
nation chemically,  condensing  into  a  substance  denominated 
phosgene  gas. 

The  preceding  remarks  comprehend  the  sum  and  substance 
of  the  knowledge  of  the  chemical  effects  of  light  previous  to 
its  application  to  the  taking  of  impressions  of  pictures  by 
the  salts  of  silver  or  otherwise.  It  is  true  that  a  certain 
Hoffmeister  published  some  vague  remarks  about  the  sun 
being  an  engraver,  several  years  previous  to  Daguerre's 
publication  ;  but  they  were  the  mere  remarks  of  one  who 
-probably  thought  the  thing  possible  without  possessing  the 
most  distant  idea  of  the  mode  of  its  effectuation.  And  in 
the  report  which  Arago  made  to  the  Chamber  of  Deputies 
in  reference  to  Daguerre's  discovery,  this  distinguished 
philosopher  mentions  the  name  of  Charles  as  having  been  in 
possession  of  a  process  for  communicating  pictures,  by  the 
aid  of  the  sun,  to  prepared  surfaces.  ~No  publication  has 
been  discovered  to  corroborate  this  assertion,  and  the  details 
of  the  operation  have  never  been  disclosed. 

The  first  recorded  attempts  by  Wedgwood*  and  Davy,f 
to  take  pictures  by  the  rays  of  the  sun  on  a  prepared  silver 

*  Wedgwood,  Josiah,  was  born  at  Newcastle-under-Lyne,  in  1730,  and  died 
in  the  year  1795. 

f  Sir  Humphry  Davy  was  born  at  Penzance,  in  1778,  and  died  at  Geneva, 
in  1828. 


14 


HISTORY  OF  PHOTOGRAPHY. 


surface,  were  published  in  the  year  1802.  The  receptacle 
of  the  picture  was  either  paper  or  leather,  or  some  other 
convenient  material,  stretched  upon  a  frame,  and  sponged 
over  with  a  solution  of  nitrate  of  silver  ;  over  this  prepared 
surface  a  painting  on  glass  was  placed  in  direct  contact  and 
exposed  to  the  rays  of  the  sun.  It  is  evident  that  the  pic- 
ture thus  obtained  Avould  be  inverted  as  to  light  and  shade. 
The  difficulty,  which  at  this  time  could  not  be  overcome, 
was  the  fixing  of  the  picture ;  and  the  process  was  aban- 
doned on  this  account.  No  chemical  substance  was  known 
whose  peculiar  properties  were  of  such  a  nature  as  to  dissolve 
the  unaltered  salt  of  silver  and  leave  the  portions  on  which 
the  image  was  projected  untouched  or  uninjured.  These  ex- 
periments of  Wedgwood  were  actually  made  several  years 
previous  to  the  publication  in  1802 ;  because  at  that  date  he 
had  been  dead  for  seven  years.  The  surface  prepared  with 
nitrate  of  silver  was  not  sensitive  enough  to  receive  an  im- 
pression in  the  camera  obscura,  although  Sir  Humphry  Davy 
succeeded  in  getting  a  very  faint  image  in  the  solar  micro- 
scope, where  the  picture  was  very  much  condensed  in  size  or 
situated  very  near  the  focus  of  parallel  rays.  From  that  date 
to  the  year  1814  not  only  no  other  publication  appeared,  but 
there  are  no  accounts  of  any  one  having  prosecuted  the  study 
of  sun-drawing.  At  this  time  a  new  laborer  entered  the  field 
of  investigation  and  directed  all  his  mental  energies  to  the 
discovery  of  means  of  making  sun-pictures.  From  the  work 
of  Daguerre,  which  was  published  several  years  later,  it  ap- 
pears that  Niepce*  was  the  first  who  obtained  a  permanent 
sun-picture  ;  to  him  we  are  indebted  for  the  first  idea  of  a 
fixing  material ;  it  was  he  who  first  employed  silver  and 
the  vapor  of  iodine.  The  process  of  Niepce  had  been  so  far 
perfected  as  to  admit  the  use  of  the  camera,  which,  by 
reason  of  the  want  of  sensitiveness  in  the  materials  used} 
had  remained  a  useless  optical  arrangement.  Niepce,  in  his 
experiments,  discarded  the  use  of  the  silver  salts,  and  sub- 
stituted in  their  place  a  resinous  substance  denominated  the 
"  Bitumen  of  Judaea."  He  named  his  process  "  Heliogra- 
phy,"  or  "  Sun-drawing."  His  pictures  were  produced  by 
coating  a  metal  plate  with  the  resinous  substance  above 
alluded  to,  and  then  exposing  this  plate,  under  a  picture  on 
glass,  or  in  the  camera,  for  several  hours  in  front  of  the  ob- 
ject to  be  copied.    By  this  exposure  to  light  the  parts  of 

*  Niepce,  Joseph-Nicephore,  was  born  at  Chalon-sur-Saone,  and  died  in 
1833. 


HISTORY  OF  PHOTOGRAPHY. 


15 


the  bitumen  which  had  been  acted  upon  by  the  rays  under- 
went a  change  according  to  the  actinic  intensity,  whereby 
they  became  insoluble  in  certain  essential  oils.  By  treat- 
ment afterward  with  these  essences,  as,  for  instance,  the  oil 
of  lavender,  the  picture  was  developed,  the  shadows  being 
formed  by  the  brilliant  surface  of  the  metal  exposed,  by 
the  solvent  action  of  the  essential  oil  in  those  parts  of 
the  resin  on  which  the  rays  of  light  had  not  impinged  ; 
whilst  the  lights  were  represented  by  the  thin  film  of 
bitumen  which  had  become  altered  and  insoluble  in  the 
oleaginous  substance  employed  in  fixing.  Some  of  the 
specimens  produced  by  this  method  at  this  period  exist  still 
in  the  British  Museum ;  some  of  them  are  in  the  form  of 
etchings,  having  been  acted  upon  probably  by  the  galvanic 
current.  It  is  evident  that  Niepce  was  acquainted  with  a 
method  of  fixing  his  sun-drawings  ;  but  his  successes  were 
limited  to  productions  which  now  would  be  regarded  very 
trivial  and  unsatisfactory.  After  ten  years'  labor  in  the 
prosecution  of  his  favorite  investigation,  by  some  accidental 
disclosure,  Nlepce  became  acquainted  with  Daguerre,*  who 
had  been  experimenting  independently  in  the  same  path. 
Daguerre's  experiments  with  chemical  processes  and  the 
camera  date  from  the  year  1824;  and  in  1829  these  two 
great  originators  of  sun-drawings  entered  into  partnership 
for  mutually  investigating  this  enchanting  art.  In  1827 
ISTiepce  had  presented  an  article  to  the  Royal  Society  of 
London  on  this  subject ;  but  as  yet  Daguerre  had  not  ar- 
rived at  any  successful  results,  nor  had  he  published  any 
thing  in  reference  to  them.  The  process  of  Daguerre  aimed 
to  perform  the  same  operation  by  the  same  method,  that  is, 
by  light ;  the  materials  for  the  sensitive  surface,  for  devel- 
oping and  fixing  alone,  being  different.  In  this  process  are 
found  the  use  of  the  camera,  iodide  of  silver  on  a  metal 
plate,  mercury  as  a  developer,  and  hyposulphite  of  soda  as  a 
fixing  agent ;  in  that  of  Niepce,  bitumen  on  a  metal  plate, 
iodine  as  a  developer,  and  oil  of  lavender  in  place  of  the 
hyposulphite  of  soda.  The  use  of  the  latter  substance  was 
probably  suggested  to  Daguerre  by  the  publication  of  a 
paper,  by  Sir  John  Herschel,  on  the  solubility  in  this  men- 
struum of  the  insoluble  salts  of  silver.  The  image  formed 
on  the  iodized  surface  was  quite  latent  until  brought  out  by 
the  vapor  of  mercury.  It  seems  wonderful  how  Daguerre 
should  hit  upon  the  idea  of  using  this  vapor,  or  that  a  latent 

*  Daguerre,  L.  J.  M.,  was  born  at  Cc-raieilles,  in  1787,  and  died  in  1851 


16 


HISTORY  OF  PHOTOGRAPHY. 


image  was  on  the  surface.  Knowing  the  latter  and  the 
possibility  of  such  a  development,  the  chemist  has  only  to 
persevere  in  a  systematic  exploration  among  the  infinite 
number  of  chemical  substances,  in  order  finally  to  meet  with 
success  ;  but  Daguerre  could  not  a  priori  be  furnished'  with 
such  positive  knowledge  ;  hence  our  admiration  at  his  suc- 
cess, at  the  hardihood  and  perseverance  of  his  character  in 
search  of  this  success,  can  not  be  otherwise  than  boundless. 
Niepce,  too,  is  entitled  to  an  .equal  share  of  honor ;  for 
without  Niepce,  in  all  probability,  sun-drawing  would  still 
be  a  latent  property  of  nature  ;  as  also,  without  Daguerre, 
the  discoveries  of  Mepce  would  not  stand  out  in  that  bold 
relief  in  which  they  are  now  exhibited. 

The  plates  which  Daguerre  used  for  the  reception  of  the 
heliographic  image  were  of  silver,  or  of  copper  plated 
with  silver.  The  silver  surface,  highly  polished,  was  sub- 
jected to  the  vapor  of  iodine  in  the  dark-chamber ;  the 
iodide  of  silver  thus  formed  being  very  sensitive  to  the 
actinic  influence,  the  plate  was  ready  for  the  reception  of 
the  latent  image.  This  mode  of  sensitizing  the  surface 
had  reduced  the  time  of  exposure  from  hours  to  minutes ; 
and  an  increase  of  sensitiveness  was  attained  at  the  sug- 
gestion of  Fizeau,  who  recommended  the  use  of  bromine- 
water  ;  and  about  the  same  time  the  chloride  of  iodine 
was  recommended  as  an  accelerator  by  Claudet ;  and  the 
bromide  of  iodine  by  Gaudin.  By  means  of  these  ac- 
celerators the  time  was  again  reduced  from  minutes  to 
seconds.  In  this  state  of  perfection  we  will  now  leave  the 
art  of  heliography,  or  of  the  Daguerreotype  as  it  is  more 
frequently  denominated,  and  observe  only,  in  conclusion,  that 
this  discovery  of  Daguerre  was  reported  to  the  world  in 
January,  1839 ;  but  the  process  was  not  communicated  until 
after  a  bill  had  been  passed  by  the  French  government, 
which  secured  to  Daguerre  a  pension  of  six  thousand  francs 
a  year,  and  to  Isidore  Niepce,  the  son  of  Daguerre's  part- 
ner, an  annual  pension  for  life  of  four  thousand  francs,  one 
half  of  which  was  to  revert  to  their  widows. 

That  Mr.  Fox  Talbot  was  acquainted  with  the  experi- 
ments of  Niepce  and  Daguerre  is  very  doubtful,  because  the 
result  of  these  experiments  was  kept  secret  until  the  pen- 
sions had  been  granted  ;  but  Mr.  Talbot  states,  in  the  com- 
munication which  he  made  to  the  Royal  Society  on  the 
thirty-first  of  January,  1839,  six  months  before  the  publica- 
tion of  Daguerre's  process,  that  he  had  been  applying  the 
property  of  discoloration  of  the  silver  salts  by  light  to  use 


HISTORY  OF  PHOTOGRAPHY. 


17 


fill  purposes.  This  application  consisted  in  preparing  a  sen- 
sitive paper  for  the  copying  of  drawings  or  paintings,  by 
direct  contact.  The  paper  was  dipped,  in  the  first  place,  in  a 
solution  of  chloride  of  sodium,  and  afterward  in  one  of 
nitrate  of  silver,  whereby  a  film  of  chloride  of  silver  was 
formed  —  a  substance  much  more  sensitive  to  light  than 
the  nitrate  of  silver,  which  had  heretofore  been  employed 
for  photographic  purposes.  The  object  to  be  copied,  which 
had  to  be  transparent,  or  partly  so,  was  applied  in  direct 
contact  with  the  sensitive  paper,  and  exposed  to  the  rays  of 
the  sun.  By  this  means,  a  copy  of  the  object  was  obtained, 
in  which  the  lights  and  shades  were  inverted.  This  was 
the  negative,  which,  when  fixed,  was  superimposed  on  an- 
other piece  of  the  sensitive  paper,  and  exposed  in  its  turn  to 
the  rays  of  light,  whereby  &  positive  print  was  obtained  of 
the  object,  in  which  the  lights  and  shades  were  exhibited  in 
their  natural  position. 

The  communication  of  Talbot  is  the  first,  which  laid  the 
foundation  of  multiplying  copies  of  a  picture  by  the  com- 
bined action  of  light  and  chemical  material ;  it  gave  the 
first  idea  of  photographic  printing. 

In  the  year  1841  another  method  was  devised  and  pa- 
tented, called  Talbotype  or  Calotype.  The  process  con- 
sisted in  preparing  paper  with  the  iodide  of  silver,  which, 
when  exposed  to  light,  became  the  recipient  of  a  latent 
image,  which  afterward  was  made  to  appear  by  the  applica- 
tion of  a  developer,  and  was  fixed  with  hyposulphite  of 
soda.  This  method  is  the  essential  point  in  the  present  col- 
lodion process ;  it  is,  in  fact,  the  very  foundation  of  photo- 
graphy. Talbot,  therefore,  merits  an  equal  position  in  his- 
tory with  Niepce  and  Daguerre.  These  three — this  much 
to  be  honored  trio — are  the  undisputed  originators  of  that 
branch  of  natural  science  which  hereafter  will  occupy  a 
prominent  part  of  human  intelligence. 

The  paper,  in  the  Calotype  process,  was  immersed  in  a 
solution  of  iodide  of  potassium,  or  floated  on  its  surface  ;  as 
soon  as  dry,  it  was  floated  on  a  solution  of  nitrate  of  silver 
for  a  certain  time.  By  this  operation,  a  film  of  iodide  of 
silver  w^as  formed  by  the  double  decomposition  of  the  two 
salts  in  contact.  The  excess  of  iodide  of  potassium,  or  of 
nitrate  of  silver  and  the  nitrate  of  potassa  were  afterward 
removed  by  washing  in  several  waters.  These  operations 
had  to  be  performed  in  the  dark  chamber,  by  the  aid  of  a 
small  candle  or  lamp.  When  the  paper  was  required  to  be 
used,  it  was  brushed  over  with  a  solution  of  one  part  of 


18 


HISTORY  OF  PHOIOGRAPHY. 


nitrate  of  silver,  containing  fifty  grains  to  the  ounce,  two 
parts  of  glacial  acetic  acid,  and  three  of  a  saturated  solution 
of  gallic  acid ;  or  the  paper  was  floated  on  the  surface  of 
this  gallo-nitrate  of  silver,  as  it  is  called,  for  a  few  seconds, 
and  the  excess  of  fluid  removed  by  blotting-paper.  By  this 
mode  of  treatment,  the  paper  was  rendered  very  sensitive, 
sufficiently  so  to  receive  an  impression  of  a  living  person,  by 
means  of  the  camera  obscura.  An  exposure  of  one  second, 
or  of  a  fraction  of  a  second,  was  found  effective  in  produc- 
ing an  impression  on  the  Calotype  paper.  This  impression 
might  be  totally  invisible,  partly  visible,  or  distinctly  visible, 
according  to  the  circumstances  of  time,  intensity  of  the 
light,  and  sensitiveness  of  the  prepared  paper.  The  latent 
image,  or  partially  visible  image,  was  then  developed  to  any 
degree  of  depth  of  shades,  by  washing  the  surface  of  the 
paper  with  one  part  of  a  solution  of  nitrate  of  silver,  of  the 
same  strength  as  before,  and  four  parts  of  the  saturated  so- 
lution of  gallic  acid.  The  image  gradually  becomes  devel- 
oped by  this  treatment,  and  in  a  few  minutes  reaches  its 
maximum  degree  of  intensity.  The  fixing  solutions  were 
bromide  of  potassium  and  hyposulphite  of  soda.  The  first 
impression,  thus  obtained,  was  in  this  process,  as  well  as  in 
that  with  chloride  of  silver,  a  negative,  which,  by  continu- 
ing the  process  and  using  this  negative  as  an  original  object, 
either  in  the  camera  or  by  direct  application,  produced  a 
positive,  with  the  lights  and  shades  in  their  appropriate 
positions. 

The  difficulty  in  this  process  is  the  want  of  homogeneity, 
and  of  a  sufficient  transparency,  in  the  structure  of  paper. 
The  want  of  transparency  probably  was  regarded  the  great- 
est drawback  in  the  production  of  negatives  ;  whilst  the  ir- 
regularities in  the  fiber  of  the  paper  could  never  yield  a  sur- 
face to  compete  with  the  brilliant  and  even  surface  of  a 
polished  piece  of  silver  for  the  reception  of  positive  pictures. 
To  obviate  these  disadvantages,  Sir  John  Herschel  proposed 
the  use  of  glass  plates,  and  was  the  first  to  employ  them. 

In  the  year  1847  Niepce  de  St.  Victor,  the  nephew  of 
Daguerre's  partner,  to  whom  we  are  indebted  for  many  in- 
teresting publications  on  the  Chromotype,  managed  to  fix  a 
film  of  albumen  on  the  glass  plates.  This  film  is  intimately 
mixed  with  the  iodides  or  bromides,  and  flowed  upon  the 
surface  of  the  glass.  Such  albumen  plates  are  employed  by 
many  very  distinguished  artists  at  the  present  day,  who  ex- 
hibit specimens  of  fine  and  sharp  definition  and  softness  of 
tone  in  their  stereographs,  that  have  not  been  surpassed  by 


HISTORY  OF  PHOTOGRAPHY. 


19 


any  other  process ;  as,  for  instance,  regard  those  beautiful 
productions  of  Ferrier. 

The  next  important  improvement  in  photography  was  ef- 
fected in  1851 ;  it  is  the  foundation-stone  of  a  ne  w  era.  Le- 
gray  originally  suggested  that  collodion  might  be  used  as 
the  receptacle  of  the  sensitive  material,  in  place  of  albumen  ; 
but  we  are  indebted  to  Archer  for  the  practical  application 
of  the  solution  of  gun-cotton,  and  of  the  mode  of  employ- 
ment, pretty  much  as  it  now  stands.  Archer  substituted pyro~ 
gallic  acid  for  the  gallic  acid  that  had  been  previously  used 
in  the  development  of  the  latent  image.  Pyrogallic  acid, 
although  still  used  as  a  developer,  has  been  since  pushed 
aside,  in  a  great  measure,  by  another  substitute,  the  sulphate 
of  the  protoxide  of  iron,  at  the  suggestion  of  Talbot.  It  is 
now  limited  principally  to  the  operation  of  intensifying. 

Collodion  is  a  solution  of  a  substance  very  much  resem- 
bling gun-cotton  in  ether  and  alcohol.  A  decided  improve- 
ment, in  many  respects,  has  been  made  in  this  solution,  at 
the  suggestion  of  Sutton,  the  editor  of  the  Photographic 
Notes,  who  recommends  an  excess  of  alcohol.  When  this 
solution  is  poured  upon  a  piece  of  clean  glass,  it  forms  a 
very  thin,  even,  and  transparent  film,  which  quickly  dries, 
and  can  scarcely  be  distinguished  from  the  surface  of  the 
glass  beneath  it.  It  contains  the  materials  for  sensitization. 
The  discovery  and  application  of  this  substance  have  given 
rise  to  what  is  denominated  the  collodion  process.  It  is  im- 
possible to  calculate  the  impetus  given  to  photography  by 
this  discovery,  or  its  value  to  society,  in  the  promotion  of 
comfort  and  happiness ;  much  less  can  an  idea  be  conceived 
of  the  resources  to  which  it  may  give  rise  by  its  future  de- 
velopments. 

In  the  year  1838  or  1839,  Mr.  Mungo  Ponton  pointed  out 
a  very  important  discovery  in  reference  to  bichromate  of 
potassa,  when  acted  upon  by  light,  whereby  this  salt,  the 
chromic  acid,  or  (as  Mr.  Talbot  advances)  the  organic  mat- 
ter with  which  the  salt  is  in  combination,  becomes  insoluble. 
The  paper  for  experimenting  on  this  point  is  uniformly  coated 
with  a  mixture  of  bichromate  of  potassa,  gelatine,  and  lamp- 
black in  cold  distilled  water,  and  allowed  to  dry  in  the  dark 
room.  When  dry,  it  is  ready  to  be  placed  beneath  a  nega- 
tive. The  time  varies  from  four  or  five  minutes  to  a  quarter 
of  an  hour  or  upward.  The  impression  obtained  in  this 
way  is  quite  latent,  and  is  made  to  appear  by  dissolving  off, 
with  hot  water,  those  parts  that  have  been  entirely  or  par- 
tially excluded  from  the  actinic  influence  of  the  light.  The 


20 


HISTORY  OF  PHOTOGRAPHY. 


picture  resulting  from  this  treatment  is  a  positive  print,  in 
black  and  Avhite,  of  which  the  shades  are  produced  by  the 
carbon  of  the  lampblack.  This  discovery  gave  rise  to  car- 
bon-printing. 

In  the  year  1852  a  patent  was  taken  out  in  England  by 
Talbot,  reserving  to  himself  the  sole  use  of  bichromate  of 
potassa  and  gelatine  in  the  production  of  photo-engravings 
on  steel.  Three  years  after  this  date,  that  is,  in  1855, 
Poitevin  patented  a  process  for  making  carbon  prints  by 
means  of  the  same  materials  combined  with  coloring  matter, 
as  well  as  for  obtaining  a  photographic  image  on  a  litho- 
graphic stone,  capable  of  being  printed  from  by  the  ordinary 
lithographic  press.  In  Talbot's  process  the  steel  plates  were 
covered  with  a  coating  of  bichromate  of  potash  and  gelatine, 
the  operation  taking  place  in  the  dark  chamber.  A  trans- 
parent positive  is  then  placed  on  its  surface,  and  the  plate  is 
then  exposed  to  the  light.  The  latent  image  is  developed 
as  before  alluded  to.  Afterward  the  edges  of  the  plate  are 
raised  with  wax,  or  some  resinous  preparation,  so  as  to  form 
a  sort  of  dish,  into  which  is  poured  the  acid  or  etching-fluid, 
which  etches  away  the  parts  exposed  by  the  removal  of  the 
soluble  gelatine.  The  etching-fluid  used  by  Talbot  was  the 
bichloride  of  platinum.  Poitevin' s  process  is  in  principle 
the  same.  The  disadvantage  in  the  latter  process  arises 
from  the  want  of  durability  in  the  image,  which,  being 
formed  out  of  organic  matter  lying,  as  it  must  do,  between 
the  ink  and  the  stone,  is  liable  to  be  soon  abraded  after  a 
few  pictures  have  been  printed  from  it.  These  attempts 
have  created  a  number  of  improvements,  by  which  matrixes 
can  now  be  furnished,  by  the  aid  of  photography,  for  the 
engraver's  press,  the  lithographic  press,  and  the  typographic 
press. 

Messrs.  Cutting  and  Bradford  took  a  patent  out,  in  this 
country,  for  a  process  in  which  the  image  is  formed  directly 
of  greasy  ink  used  in  lithography. 

The  next  important  step  in  photo-lithography  is  that  in 
which  the  picture  is  first  formed  by  bichromate  of  potash 
and  gelatine  on  lithographic  £rans/er-paper,  that  is,  paper 
coated  with  a  layer  of  albumen.  A  negative  is  placed  m 
direct  contact  with  paper  so  prepared,  from  which  an  image 
is  obtained,  that  is,  after  certain  other  operations,  transferred 
directly,  in  lithographic  ink,  to  the  stone.  This  process  was 
patented  in  1859,  at  Melbourne,  in  Australia,  by  Mr.  Osborne, 
for  which  he  was  awarded  by  the  government  of  the  colony 
of  Victoria  the  sum  of  one  thousand  pounds.    This  process 


HISTORY  OF  PHOTOGRAPHY. 


21 


promises  to  be  the  basis  of  the  most  successful  operations  in 
photo-lithography. 

Asser,  of  Amsterdam,  invented  or  used  the  transfer  pro- 
cess at  the  same  time  that  Osborne  was  using  it  in  Aus- 
tralia. 

Colonel  Sir  Henry  James  makes  use  of  zinc,  upon  which 
he  transfers  the  image  formed  in  ink ;  the  image  having  been 
produced  on  engraver's  tracing-paper  by  the  means  adopted 
by  Talbot,  Poitevin,  and  Osborne. 

In  the  year  1859  another  process  for  photo-lithographic 
purposes  was  patented  in  Vienna,  in  Austria,  in  which  as- 
phaltum  is  again  brought  into  the  field.  The  developer  is 
oil  of  turpentine  and  water.  The  latent  image  is  produced 
in  a  film  consisting  of  a  solution  of  asphaltum  in  chloroform, 
by  means  of  a  collodion  negative  exposed  for  a  number  of 
hours.  As  soon  as  the  soluble  asphaltum  has  been  removed, 
the  remaining  insoluble  parts  which  form  the  shades  of  the 
image  are  coated  with  a  layer  of  ink  by  the  printer ;  the 
image  is  then  gummed  in,  and  slightly  etched ;  after  which 
it  is  ready  for  the  press. 

Poitevin  has  just  published  a  new  method  of  direct  car- 
bon-printing on  paper,  It  depends  upon  the  insolubility 
communicated  to  certain  organic  matters,  such  as  gum,  al- 
bumen, gelatine,  etc.,  by  the  per-salts  of  iron,  and  on  a  new 
fact  observed  by  him,  namely,  that  this  matter,  coagulated 
and  rendered  insoluble  in  cold  and  even  in  hot  water,  be- 
comes soluble  under  the  influence  of  light,  and  in  contact 
with  tartaric  acid,  which,  by  the  reduction  of  the  iron  salt, 
restores  to  the  organic  matter  its  natural  solubility.  The 
paper  for  carbon-printing  is  floated  in  a  bath  of  gelatine 
dissolved  in  water  and  colored  with  a  sufficient  quantity  of 
lampblack,  or  other  coloring  matter,  and  maintained  at  a 
lukewarm  temperature.  The  paper  becomes  thus  uniformly 
covered  with  the  colored  gelatine. 

The  sensitizing  part  is  performed  in  the  dark  room  by 
plunging  each  sheet  into  a  solution  of  sesquichloride  of  iron 
and  tartaric  acid  in  water.  By  this  immersion  the  gelatine 
becomes  quite  insoluble  even  in  boiling  water.  The  sheets 
are  taken  out  and  dried.  The  prints  are  obtained  by  placing 
transparent  positives  in  direct  contact  with  the  paper  in  the 
printing-frame.  Two  or  three  minutes'  exposure  to  the  rays 
of  the  sun  will  be  found  sufficient  to  render  those  parts 
through  which  the  light  has  passed  soluble  in  boiling  water, 
which  is  the  developer  and  fixing  agent  at  the  same  time. 
A  little  acid  water  is  used  toward  the  end  of  the  washing,  in 
order  to  remove  all  traces  of  the  ferruginous  compound. 


22 


HISTORY  OF  PHOTOGRAPHY. 


Poitevin  has  other  methods  of  producing  direct  carbon- 
prints,  which,  together  with  this  and  others  preceding,  will 
be  fully  discussed  in  their  proper  place. 

Niepce  de  St.  Victor  has  long  been  experimenting  in  his 
favorite  study  of  the  chromotype.  He  has  succeeded  in  pro- 
ducing photogenic  impressions  endowed  with  certain  colors 
of  the  original.  Yellow  is  found  very  difficult  to  transfer  to 
the  heliochromic  plate  at  the  same  time  with  other  colors. 
Red,  green,  and  blue,  it  appears,  could  be  formerly  repro- 
duced satisfactorily.  In  the  fifth  memoir  of  Niepce  on  this 
subject,  the  author  states  that  he  can  now  reproduce  yellow 
along  with  other  colors  in  a  definite  manner.  The  trouble 
with  these  heliochromic  specimens  is  still  their  want  of  per- 
manence. At  the  very  most,  the  colors  can  not  be  preserved 
longer  than  two  or  three  days.  The  problem  to  be  settled 
is  the  means  and  mode  of  fixation. 


CHAPTER  II. 


PRELIMINARY  OBSERVATIONS. 

The  art  of  Photography  comprehends  all  the  operations 
of  taking  a  picture  on  a  sensitive  surface  by  means  of  light 
and  chemical  reagents.  These  operations  are  as  varied  as 
the  different  substances  on  which  they  are  taken,  or  by 
which  they  are  taken.  In  all  cases,  whatever  may  be  the 
process,  the  conditions  required  in  the  operation  of  pro- 
ducing a  photographic  image  are,  firstly,  a  suitable  ground- 
work or  receptacle,  such  as  paper,  metal,  glass,  or  stone ; 
secondly,  a  coating  of  substances  called  sensitizers,  which 
are  very  sensitively  affected  by  light  and  altered  according 
to  its  intensity ;  thirdly,  chemical  ingredients,  denominated 
developers,  that  act  differently  upon  the  parts  that  have 
been  changed  by  light  from  what  it  does  upon  the  parts 
upon  which  light  has  not  acted  at  all  or  feebly  ;  fourthly, 
fixing  agents  or  chemical  solvents  of  the  sensitizing  agents 
that  have  not  been  changed  by  light.  Other  important  con- 
ditions are  comprehended  in  the  light,  requiring  it  to  be  of 
a  certain  intensity,  in  a  certain  direction,  and  in  a  certain 
quantity. 

The  various  sorts  of  matter  for  the  reception  of  the  pho- 
tographic image  have  given  rise  to  a  variety  of  processes, 
whose  appellations  refer  rather  to  the  material  employed 
than  to  any  difference  in  the  actinic  principle ;  thus,  on 
paper,  exist  a  number  of  so-called  processes,  as,  for  instance, 
printing  by  direct  contact,  and  printing  by  development ; 
the  plain-paper  process,  the  wax-paper  process,  the  resin 
process,  and  the  albumen  process.  On  glass  are  found  the 
negative  process,  the  positive  or  ambrotype  process,  and  the 
transfer  process.  On  metal  the  melainotype  and  daguerreo- 
type processes  and  photo-engraving ;  and  on  stone,  photo- 
lithography. In  addition  to  these  may  be  mentioned  the 
card-picture  process  and  that  of  the  stereograph.  In  refer- 
ence to  the  materials  used  in  the  sensitized  photographic 
film,  or  rather  to  contain  the  sensitizing  ingredients,  stand 


24 


PRELIMINARY  OBSERVATIONS. 


out  most  prominently ;  the  Collodion  processes,  wet  and  dry, 
the  Tannin  process,  and  the  Albumen  process. 

The  sensitizing  substances  most  generally  used  are  the 
salts  of  silver  in  combination  with  organic  matter.  In  the 
carbon  process,  as  also  in  photo-lithography,  photo-engrav- 
ing, photo-zincography,  and  photo-glyphography,  the  sensitive 
materials  are  gelatinous  or  resinous  substances  in  combina- 
tion with  certain  chemical  reagents  that  render  them  insolu- 
ble, and  in  which  the  solubility,  in  certain  menstrua,  is  again 
restored  by  the  agency  of  light.  The  salts  that  have  hitherto 
been  used  are  the  bichromate  of  potassa  and  the  sesqui-salts 
of  iron ;  the  receptacles,  asphaltum  and  gelatine ;  and  the 
solvents,  hot  water,  oil  of  turpentine,  and  oil  of  lavender. 
The  fixing  agents  or  solvents  of  the  undecomposed  iodides, 
bromides,  and  chlorides  of  silver  in  the  collodion,  albumen, 
or  surface-sensitized  film,  on  which  the  rays  of  light  have 
not  acted,  or  but  partially  acted,  are  hyposulphite  of  soda, 
cyanide  of  potassium  and  sulphocyanide  of  ammonium.  The 
chemical  reagents  that  either  develop  the  latent  image  or 
perfect  that  which  light  has  already  commenced,  are  the 
proto-salts  of  iron,  ammonia,  gallic  and  pyrogallic  acid, 
formic  acid,  and,  in  the  daguerreotype-plate,  mercury. 
Other  materials  are  used  in  addition  to  intensify  the  image 
already  formed  by  the  ordinary  developers.  The  principle 
involved  in  the  strengthening  of  negatives  is,  first,  probably 
by  certain  electrical  decompositions,  to  produce  a  deposit 
on  the  shadows  formed  by  means  of  silver,  mercury,  lead,  or 
iodine  ;  and  secondly,  to  blacken  this  deposit  by  sulphuriz- 
ing or  reducing  agents,  or  by  the  alkalies. 

The  great  divisions  into  which  photographic  operations 
may  be  divided  are  those  which  treat  of  negatives  and  posi- 
tives. A  negative  is  an  actinic  inrpression  on  glass  or  waxed 
paper,  in  which  the  lights  and  shadows  are  inverted,  as  also 
the  figures  and  the  different  items  that  form  the  picture ; 
that  is,  right  becomes  left,  and  left  right.  The  negative  is 
the  matrix  from  which  photographic  prints  are  obtained 
either  on  paper  or  other  material ;  these  prints  are  produced 
either  by  direct  contact  of  the  paper  or  glass  with  the  nega- 
tive, or  the  negative  is  placed  in  one  focus  of  a  camera,  and 
the  paper  or  glass  in  its  conjugate  focus.  Such  prints  or 
impressions,  whether  by  reflected  or  transmitted  rays,  are 
positives,  in  which  the  lights  and  shades,  as  well  as  all  the 
delineations,  are  in  their  true  and  natural  position.  There 
is  another  class  of  positives  in  which  the  shading  is  natural, 
'but  the  delineations  are  inverted ;  these  are  exemplified  in 


PRELIMINARY  OBSERVATIONS. 


25 


tlie  daguerreotype,  ambrotype,  and  melainotype,  which  are 
exhibited  only  by  reflected  light. 

As  the  present  work  is  intended  for  practical  men,  it  will 
be  necessary  at  the  very  outset  to  give  a  list  of  all  the  arti- 
cles and  arrangements  required  in  the  successful  pursuit  of 
the  photographic  art. 

LIST  OF  A  PHOTOGRAPHIC  OUTFIT. 

1.  Glass-house,  or  room  in  the  garret  furnished  with  a 
sky-light. 

2.  Dark  room,  for  sensitizing  plates  or  papers. 

*     3.  Operating  room,  for  collodionizing  plates,  mounting 
prints,  etc. 

4.  Screens  (white,  gray,  blue,  and  artistic)  for  the  glass- 
house. 

5.  Lenses,  (|,     £ ,  etc.,  stereoscopic  and  orthoscopic.) 

6.  Cameras,  (for  portraits,  views,  stereographs,  and  for 
copying.) 

V.  Ornamental  carpets,  chairs,  stands,  curtains,  pillars, 
balustrades,  etc. 

8.  Head-rests,  etc.,  camera-stands,  mirrors,  brushes,  combs, 
pins,  needle,  and  thread. 

9.  Washhand-stand,  pitcher  and  basin,  soap  and  towels, 
clothes-brush  and  nail-brush. 

10.  Stove,  tongs,  shovel,  poker,  coal  or  wood-box. 

11.  Antechamber,  suitably  furnished  with  lounges,  etc. 

12.  Show-cases  for  artistic  productions,  and  cases  for 
chemicals,  etc. 

13.  Collodion,  (negative  and  positive,)  acetic  acid,  nitric 
acid,  citric  acid,  tartaric  acid,  protosulphate  of  iron,  gallic 
acid,  pyrogallic  acid,  formic  acid,  carbonate  of  soda,  car- 
bonate of  lime,  (chalk,)  chlorinetted  lime,  nitrate  of  silver, 
citrate  of  soda,  phosphate  of  soda,  blue  litmus-paper,  red 
litmus-paper,  sulphide  of  potassium,  sulphocyanide  of  am- 
monium, ammonia,  oxide  of  silver,  iodide  of  potassium, 
iodide  of  ammonium,  iodide  of  cadmium,  iodine,  tincture  of 
iodine,  bromide  of  potassium,  bromide  of  ammonium,  bro- 
mide of  cadmium,  bromine,  nitrate  of  uranium,  bichloride 
of  mercury,  gum-arabic,  starch,  gelatine,  glue,  shellac, 
chloride  of  gold,  acetate  of  soda,  alcohol,  ether,  distilled 
water,  loaf-sugar,  cyanide  of  potassium,  hyposulphite  of 
soda,  pyroxyline,  sulphuric  acidj  rotten-stone,  tannin,  sesqui- 
chloride  of  iron,  oxalic  acid,  varnish,  hydrochloric  acid, 
acetate  of  lead,  caustic  potassa,  salts  of  tartar,  chloride  of 
sodium,  chloride  of  ammonium,  bichromate  of  potassa,  as- 


2G 


PRELIMINARY  OBSERVATIONS. 


phaltuni,  copal,  chloroform,  cotton,  nitroglucose,  mastic, 
resin,  thus,  benzoin,  benzine,  wax. 

14.  Funnels,  filtering-stands,  collodion-glasses,  developing 
and  fixing-glasses,  porcelain  or  photographic-ware  baths  and 
dishes,  filtering-paper,  plain  paper,  plain-salted  paper,  albu- 
men paper,  arrowroot  paper,  tinted  paper,  resinized  paper, 
wax  paper,  blotting  paper,  plate-cleaners,  plate-holders,  Can- 
ton flannel,  cotton  cloths,  silk  cloths,  brushes,  colors,  pencils, 
scale  and  compasses,  magnifying-glass,  cases,  mats,  preserv- 
ers, glass  plates  of  various  sizes,  (transparent  and  ground,) 
melainotype-plates,  black  leather,  black  velvet,  black  var- 
nish, black  paper,  scissors,  pliers,  pens,  ink,  paper,  post- 
stamps,  envelopes,  pocket-knife,  black  lead-pencils,  gutta- 
percha dishes,  pails,  towels,  pitcher,  ice-cooler,  soft  water, 
focussing-cloths,  brooms,  hand-brush,  diamond,  cutting- 
board  for  glass,  shelves  for  negatives,  drawers  for  mounts, 
papers,  etc.,  beaker-glasses,  wash-tubs,  scales,  weights  and 
graduated  measures,  dropping-tubes,  test-tubes  and  rack, 
evaporating-dishes,  crucibles  and  furnace,  tongs,  coal  or 
wood,  door-mats,  hat-stand,  artificial  paraphernalia,  as  stuffed 
birds,  beasts,  etc.,  skeletons,  vases,  printing-boxes,  fuming- 
boxes,  forms  for  cutting  out  stereographs,  card-pictures,  etc., 
card-board,  mounts  of  various  sizes,  spatula,  pestle  and  mor- 
tar, India-rubber,  lamps,  candles,  frames  for  photographs, 
solar  camera  and  its  appendages,  solar  microscope  and  acces- 
sories, glue-pot,  tea-kettle,  changing-box  for  dry  plates. 

15.  For  out-door  work  will  be  required  extra :  a  small 
hand-cart  and  tent,  or  dry  collodion  or  tannin-plates,  wax- 
paper,  graduated  tape,  saw,  hatchet,  hammer  and  nails, 
negative-holder. 


CHAPTER  III. 


SPECIALTIES  IK  REFERENCE  TO  THE  ARTICLES  IN  THE  PRE- 
CEDING CHAPTER  THE  GLASS-HOUSE,  ETC. 

The  first  thing  which  claims  the  attention  of  the  photo- 
grapher, is  to  secure  to  himself  suitable  rooms.  In  many 
instances  the  artist  has  the  privilege  of  superintending  the 
construction  of  his  glass-house  or  operating-rooms  ;  in  this 
case  he  must  not  only  know  what  is  required  in  such  a  con- 
struction, but  he  must  know  what  arrangements  are  the 
most  appropriate.  The  success  of  many  an  artist  depends 
upon  the  fortuitous  advantages  of  his  glass-house ;  but  these 
fortuitous  advantages  depend  upon  fixed  laws  and  principles 
which  the  photographer  must  learn,  if  he  is  still  ignorant 
of  them.  To  be  brief,  contrast  between  light  and  shade  is 
agreeable  to  the  eye,  whether  tutored  or  untutored ;  where- 
as uniformity  of  light  or  of  shade  is  very  displeasing.  It  is 
not  known  why  this  is  so  any  more  than  why  harmonious 
combinations  of  notes  are  delightful  to  the  ear,  or  why  non- 
coincident  vibrations  produce  discord.  By  means  of  a  hap- 
pily arranged  contrast  of  light  and  shade,  a  stereographic 
roundness  is  communicated  to  pictures  which,  where  this 
contrast  is  deficient  or  quite  wanting,  are  flat  and  in  no  way 
satisfactory ;  and  where  the  contrast  is  exaggerated — where 
the  lights  are  very  bright  and  the  shades  very  deep — where 
the  transition  from  one  to  the  other  is  direct,  and  the  line 
of  demarcation  between  them  is  almost  visible  —  the  round- 
ness becomes  a  complete  distortion  of  solidity.  This  distor- 
tion, arising  from  a  vulgar  contrast,  is  sometimes  so  great 
as  to  cause  the  sitter  to  disclaim  his  own  picture.  The 
qualifications  of  an  artist  are  very  distinct  from  those  of  a 
mere  operator ;  the  former,  by  reason  of  his  qualifications, 
can  associate  with  gentlemen  and  the  intelligent ;  the  latter 
can  aspire  to  no  higher  companionship  than  with  the  igno- 
rant and  vulgar.  But  the  qualifications  in  question  are  at- 
tributable, in  a  great  measure,  to  a  thorough  knowledge  of 


28 


SPECIALTIES — THE  GLASS-HOUSE,  ETC. 


light  in  reference  to  his  art,  whereby  nature  becomes  na+ 
tural. 

If  an  object  be  placed  so  that  the  light  in  one  direction, 
whether  brilliant  or  dull,  falls  perpendicularly  upon  its  sur- 
face, the  picture  will  be  flat  and  disagreeable,  because  there 
is  no  contrast ;  if  the  light  falls  obliquely,  the  contrast  will 
be  displeasing  according  to  its  intensity,  because  the  shadows 
will  be  elongated  and  distinctly  marked  from  the  lights.  A 
single  light,  therefore,  can  scarcely  be  said  to  produce  an 
artistic  satisfaction. 

Two  equally  bright  lights,  in  opposite  directions,  or  rather 
in  directions  at  right  angles  to  each  other,  are  very  objection- 
able, because  either  produces  a  bright  circle  of  light  in  the 
eyes,  which  is  repugnant  to  an  artist's  feelings,  from  the  fact 
that  the  picture  is  severely  flat  for  want  of  contrast. 

If  lights  proceed  from  two  directions,  at  right  angles  to 
each  other,  or  somewhere  in  the  neighborhood  of  this  angle, 
of  which  one  is  more  brilliant  than  the  other,  then  it  is  pos- 
sible so  to  arrange  the  sitter  or  model  as  to  satisfy  a  culti- 
vated taste. 

The  greater  the  brilliancy  of  the  light,  the  more  unman- 
ageable it  becomes  in  the  production  of  that  soft  merging  of 
light  into  shade  which  in  photography  is  so  much  required* 
It  is,  therefore,  quite  objectionable  to  use  the  direct  rays  of 
the  sun  in  taking  portraits.  But  during  the  day  these  rays 
proceed  from  three  directions  of  the  compass — in  the  morn- 
ing from  the  east,  at  noon  from  the  south,  and  in  the  evening 
from  the  west ;  from  the  north  alone,  in  the  northern  hemi- 
sphere, the  rays  never  emerge.  But  the  northern  sky  or 
space  is  illumined  by  the  direct  light  from  the  sun,  which, 
by  reflection  and  diffusion,  has  parted  with  much  of  its  of- 
fensive brilliancy,  and  is  rendered  soft  and  manageable. 
The  direct  light  into  the  glass-house,  therefore,  must  enter 
from  the  north;  this  is  the  light  which  performs,  or  is  to  per- 
form, the  principal  part  in  the  production  of  a  negative. 
Now  this  single  light,  which  enters  from  the  northern  part 
of  the  hemisphere,  or  a  portion  of  it  at  least,  may  be  soft- 
ened down  by  reflection  from  side-screens,  and  so  directed 
by  them  upon  the  sitter  as  to  make  any  degree  of  agreeable 
contrast.  With  these  principles  in  view,  the  glass-house 
must  be  constructed.  If  the  operating-room  is  situated  in 
the  highest  story  of  a  house,  this  house  ought  to  be  at  least 
as  high  as  the  adjoining  or  contiguous  buildings ;  and  the 
glass  window  on  the  roof  must  be  quite  unobstructed  by 
chimneys  or  trees  in  a  direction  perpendicular  to  its  surface. 


SPECIALTIES — THE  GLASS-HOUSE,  ETC.  29 


Supposing  the  ends  of  the  building  in  which  it  is  required  to 
construct  a  photographic  establishment  face  east  and  west, 
the  following  arrangement  is  one  which  I  would  recommend : 
Let  the  southern  side-wall  be  raised  until  it  is  as  high  as  the 
ridge  of  the  roof ;  in  like  manner  fill  up  to  the  same  height 
the  triangular  space  in  the  end- wall  between  the  chimney 
and  the  southern  wall  now  raised,  either  on  the  eastern  or 
western  end,  as  it  may  happen  to  be  ;  at  a  distance  of  fif- 
teen feet  from  the  end-wall  raise  another,  equally  high,  and 
parallel  with  it,  from  the  southern  side  to  the  ridge  of  the 
roof.  Next  construct  a  water-tight  flat  roof,  beginning  at 
the  side  and  running  toward  the  north  about  ten  feet.  Where 
this  terminates,  introduce  the  wooden  frame,  the  southern 
portion  inclining  to  the  horizon  toward  the  north  at  an  angle 
of  forty-five  degrees,  to  contain  the  sky-light,  which  may  be 
fifteen  feet  wide  by  twelve  feet  deep,  and  inclined  at  an  angle 
of  forty-five  degrees  with  the  horizon  and  facing  the  north ; 
the  southern  part  of  the  frame  and  the  window,  therefore, 
comprehend  a  right  angle.  Where  it  is  practicable,  it  is 
well  to  have  a  window  in  either  of  the  end-walls,  furnished 
with  sets  of  tight  shutters  about  four  feet  wide,  and  pro- 
+  ceeding  (in  direct  contact,  at  the  commencement,  with  the 

part  of  the  sky-light  nearest  the  north)  downward  to  within 
two  feet  from  the  floor.  Such  side-lights  can  frequently  be 
used  instead  of  screens  ;  and  by  the  adjustment  of  the  shut 
ters,  light  can  be  admitted  as  required,  either  as  regards 
quantity  or  direction,  that  is,  from  the  west  in  the  morning, 
and  from  the  east  in  the  evening.  From  the  lowest  part  of 
the  skylight  downward,  and  right  across  the  room,  the  space 
is  boarded  up  about  four  feet  deep,  and  then  the  remaining 
part  overhead  is  a  flat  ceiling  as  far  as  the  northern  side  of 
the  building.  The  length  of  this  room  must  be  about  thirty 
feet.  The  dark-chamber  and  the  ordinary  work-room  may 
be  constructed  on  the  northern  side,  the  window  of  one 
being  glazed  with  an  orange-yellow  colored  glass,  in  order 
to  absorb  the  actinic  rays,  and  the  other  with  common  crown- 
glass.  On  the  outside  of  the  side-windows,  small  platforms 
are  formed  for  the  reception  of  the  printing-frames,  where 
no  other  room  can  be  had  separately  and  especially  for  the 
direct-printing  department.  The  sky-light  and  the  side- 
lights have  to  be  furnished  with  curtains,  in  order  to  soften 
or  modify  the  light,  which  has  access  according  to  the  cir- 
cumstances of  the  case  or  the  taste  of  the  artist.  The  back- 
grounds are  placed  in  the  space  beneath  the  flat  roof,  on  the 
southern  side,  and  so  far  back  as  to  cut  off*,  as  much  as  pos- 


30 


SPECIALTIES — THE  GLASS-HOUSE,  ETC. 


sible,  the  direct  rays  upon  the  head  of  the  sitter.  The 
northern  end  must  be  papered  with  a  grayish-colored  paper 
— the  more  uniform  the  better — so  as  to  keep  this  part  as 
feebly  lighted  as  possible.  It  is  even  advisable  to  have  the 
part  where  the  camera  is  situated  entirely  curtained  off  from 
the  remaining  space  ;  by  such  an  arrangement,  the  operator 
requires  no  focussing-cloth,  and  the  curtains  being  of  some 
material  such  as  wool,  and  of  a  deadened  color,  the  sitter's 
eyes  are  never  strained  by  looking  in  this  direction. 

It  happens,  however,  very  frequently,  that  photographers 
can  not  direct  the  construction  of  their  rooms,  and  that  the 
sky-light  is  inserted  directly  into  the  slanting  side  of  the 
roof.  In  this  case,  if  the  light  comes  from  the  north,  the 
room  will  have  a  direction  from  east  to  west,  the  sitter  being 
placed  at  either  end,  according  to  circumstances.  Here  only 
one  side-light  can  be  used ;  to  compensate  the  want  of  a 
southern  side-light,  a  screen,  movable  on  an  axis,  is  placed 
in  its  stead,  which,  receiving  light  either  from  above  or  the 
opposite  side,  can  be  made  to  reflect  the  same  in  the  direc- 
tion required. 

Where  the  ridge  of  the  roof  of  a  building  is  directly 
north  and  south,  and  a  sky-light  has  to  be  constructed  on  the 
slanting  roof,  there  seems  to  be  no  alternative  but  to  make 
two  sky-lights,  one  on  either  side,  furnished  with  thick  cur- 
tains within,  and  on  the  outside  with  a  tall  partition  be- 
tween them,  as  also  one  on  the  southern  side,  to  exclude  the 
direct  rays  of  the  sun ;  or  to  construct  a  suite  of  rooms,  by 
raising  one  of  the  side-walls  of  the  building  as  nearly  in  ac- 
cordance with  the  plan  first  proposed,  with  those  exceptions 
only  which  the  nature  of  the  building  would  demand.  For 
instance,  if  the  building  were  somewhat  wide,  there  would 
be  only  one  side- window,  and  the  facilities  for  printing  would 
not  be  so  great,  unless  some  room  could  be  fixed  up  with  a 
southern  aspect.  The  illumination  of  the  background  by 
the  light  from  the  sky-light,  just  described,  is  uniform,  be- 
cause the  construction  of  the  frame  admits  an  equal  quantity 
at  the  top  as  well  as  at  the  bottom.  The  ordinary  mode  of 
erecting  the  southern  part  of  the  frame,  which  supports  the 
sky-light  in  a  position  perpendicular  to  the  horizon,  excludes 
much  of  the  light,  and  forms  a  shadow  on  the  upper  part  of 
the  background,  unless  a  contrivance  of  reflection  over- 
head causes  the  illumination  to  be  equally  and  uniformly 
distributed. 

The  screens  or  backgrounds  for  placing  behind  the  model 


SPECIALTIES — THE  GLASS-HOUSE,  ETC. 


31 


are  various.  If  the  background  is  to  be  quite  white,  the 
screen  must  be  white ;  if  intermediate  between  black  and 
white,  the  screen  may  be  gray,  grayish-blue,  blue,  and  vio- 
let. A  red,  orange-red,  yellow,  and  black  screen  will  pro- 
duce a  dark-colored  background,  from  the  fact  that  light, 
impinging  upon  such  surfaces,  reflects  scarcely  any  but  three 
colors,  and  absorbs  almost  all  the  rest ;  but  these  colors  are 
known  by  experience  to  be  possessed  of  little  or  no  actinic 
influence.  Screens  with  graduated  tints,  shading  off  from 
one  color  into  another,  or  gradually  shading  off  from  a  deep 
to  a  light  color,  are  to  be  highly  recommended  to  an  artistic 
operator.  Other  screens  again  represent  landscapes,  castles, 
shipping,  city  scenery,  etc.,  in  dark-colored  outlines  and 
shading,  on  a  gray  or  bluish-gray  foundation.  Such  repre- 
sentations are  very  pleasing  to  the  uneducated  taste  ;  the 
true  artist  sometimes  seems  to  regard  them  as  finical.  If 
such  backgrounds  are  in  true  perspective,  are  correct  repre- 
sentations of  natural  objects  and  scenery,  and  can  be  well 
focussed  on  the  ground-glass,  I  would  not  hesitate  to  pro- 
nounce them  legitimately  artistic,  and  as  such  they  must  en- 
hance the  value  of  a  card-picture  or  other  photograph.  On 
the  contrary,  if  the  productions  are  rude,  faulty,  and  care- 
lessly shaded,  their  images  on  the  collodion-film  will  be 
equally  so,  and  even  more  so,  by  distortion  from  the  lenses, 
and  will  tend  to  communicate  to  the  photograph  a  vulgar 
appearance. 

On  the  subject  of  light,  a  few  words  more  will  suffice  in 
this  section.  Place  the  model  in  a  very  easy  and  graceful 
manner,  either  standing  or  sitting,  leaning  on  a  pillar,  balus- 
trade, or  small  stand,  in  such  a  manner  that  every  part  is 
nearly  equally  in  focus,  but  especially  the  hands,  face,  and 
feet,  (if  the  latter  are  to  be  visible.)  Avoid  as  much  as  pos- 
sible that  silly  clinging  to  uniformity  in  the  position  of  the 
sitter,  which  some  operators  fall  into,  as  of  laying  the  hands 
folded  together  on  the  lap,  or  of  fixing  the  thumb  in  the  arm- 
hole  of  the  vest.  Such  sameness  becomes  a  characteristic 
of  the  gallery,  and  renders  the  specimens  that  proceed  from 
it  ridiculous.  Old  and  young,  handsome  and  ugly,  the 
grieved  and  the  joyous,  have  all  been  invested  in  the  same 
exuvise,  have  all  been  grouped  or  posed  amid  the  same  ac- 
coutrements. Above  all  things,  endeavor  at  least  to  pro- 
duce a  variety  of  position  and  paraphernalia  in  the  respect- 
ive members  of  one  and  the  same  family ;  otherwise,  your 
photographs  wil  l  be  no  better  than  the  painting  of  Dr. 


32 


SPECIALTIES  THE  GLASS-HOUSE,  ETC. 


Goldsmith's  family  in  the  Vicar  of  Wakefield,  in  which  is 
beheld  an  orange  in  the  hand  of  each  figure.  As  soon  as 
the  figure  or  group  is  fixed  in  a  pleasing,  an  easy,  and  artistic 
position,  the  next  and  a  very  important  business  presents  it- 
self, which  consists  in  illuminating  this  figure  or  group  in 
such  a  way  as  to  obtain  a  clear  and  distinct  image  on  the 
ground-glass  of  the  camera.  If  the  light  falls  too  much  on 
the  head,  prevent  this  by  means  of  the  curtain  on  the  sky- 
light ;  if  the  shadows  are  too  strong,  and  apparent  beneath 
the  eyebrows,  nose,  or  chin,  correct  this  defect  by  means  of 
the  side-light  or  the  movable  screen,  recollecting  the  first 
law  of  reflection  of  light,  which  teaches  that  the  angle  of 
incidence  is  equal  to  the  angle  of  reflection,  so  that,  if  th6 
screen  be  inclined  to  the  horizon  at  an  angle  of  forty-five 
degrees,  rays  that  fall  upon  it  through  the  sky-light  will  pass 
off  from  it  in  a  direction  parallel  with  the  horizon,  and  in  a 
good  condition  for  destroying  those  horrid  black  specks  of 
shadow  wherever  there  exist  prominences  or  cavities.  The 
great  art  in  photography  is  to  simplify  the  light  to  the  very 
utmost,  to  use  if  possible  light  from  two  directions  alone, 
and  only  that  sort  of  light  which  is  endowed  with  actinic 
influence  on  the  sensitized  plates.  It  will  frequently  hap- 
pen that,  with  the  most  brilliant  illumination,  no  other  but 
a  hazy  image  of  the  model  can  be  obtained  on  the  ground- 
glass  ;  and  where  this  image  is  thus  indistinct  and  fuzzy  on 
the  ground-glass,  it  is  utterly  impossible  to  obtain  any  better 
result  on  the  film  of  collodion.  The  haziness  in  question  is 
caused  by  a  multiplicity  of  reflections  of  light,  by  which 
rays  interfere,  cross  each  other,  and  are  jumbled  together  in 
a  very  irregular  and  heterogeneous  manner,  and  also  by  the 
impure  and  unequally  dense  layers  of  air  and  vapor  set  in 
motion  in  the  room,  which  produce  an  atmosphere  in  front 
of  and  around  the  sitter  similar  to  those  dazzling  ascending 
columns  of  air  visible  at  the  sides  and  on  the  top  of  a  stove. 
To  avoid  the  first  cause,  it  is  recommended  to  glaze  the  sky- 
light with  glass  containing  cobalt,  which  communicates  to  it 
a  blue  or  violet  tinge.  Such  glass  excludes  all  superfluous 
light,  allows  only  actinic  rays  to  penetrate,  and  subdues  the 
illumination  to  such  a  degree  as  to  render  the  image  on  the 
ground-glass  quite  distinct  and  agreeable  to  the  eye.  Al- 
though the  room,  by  such  glazing,  is  considerably  darkened, 
the  operations  in  photography  are  incomparably  superior  in 
result,  and  the  time  of  exposure  is  not  lengthened.  The 
Becond  cause  is  obviated  by  preserving  a  uniform  tempera- 


SPECIALTIES  THE  GLASS-HOUSE,  ETC. 


38 


ture  in  the  room,  and  by  having  the  currents  of  ventilation 
proceeding  to  their  exit  at  some  distance  from  the  sitter. 
Let  me  finally  impress  upon  every  photographer  the  abso- 
lute necessity  he  is  placed  in  of  learning  to  manage  the 
light,  before  he  can  ever  hope  to  be  successful  in  the  subse- 
quent operations  with  chemical  materials.  An  imperfectly 
lighted  picture  can  never  be  metamorphosed  afterward  into 
a  respectable  production 


CHAPTEE  IV. 


SPECIALTIES  CONTINUED. — THE  CAMERA  AND  LENS. 

The  second  most  essential  thing  after  a  good  light,  and  a 
successful  illumination  of  the  object,  is  a  compound  lens,  so 
far  corrected  for  spherical  and  chromatic  aberration  as  to 
reproduce  on  the  ground-glass  an  image  in  which  straight 
lines  are  exhibited  straight,  and  all  the  parts,  both  in  the 
central  and  peripheral  portions,  are  clearly  defined  and  free 
from  spectral  colors.  No  single  lens  can  be  practically 
ground  and  polished  so  as  to  be  free  from  spherical  aberra- 
tion ;  which  means  that  no  lens  can  be  constructed  so  that, 
with  the  whole  opening,  the  rays  both  through  the  center 
and  all  the  way  to  the  edges  shall  be  refracted  to  one  point. 
The  focus  of  those  rays  which  are  transmitted  through  the 
lens  near  the  periphery,  is  nearer  to  the  lens  than  of  those 
which  pass  through  the  center.  Hence  exist  a  multiplicity 
of  foci,  thus  converting  that  which  ought  to  be  a  point  into 
a  circular  space  ;  and  that  which  ought  to  be  a  line,  into  a 
rectangular  or  curvilinear  space ;  hence  the  origin  of  indis 
tinctness  and  haziness  in  the  photograph — the  picture  is  de- 
void of  sharpness  and  fine  definition.  If  the  optician  were 
able  to  grind  lenses  with  ellipsoidal  surfaces,  then  a  single 
lens  might  be  constructed  so  as  to  be  totally  free  from  this 
sort  of  error  or  aberration.  This,  however,  is  manifestly  a 
practical  impossibility.  The  form  of  lens  which  distorts 
the  least,  that  is,  which  has  the  least  spherical  aberration, 
is  the  one  which  is  well  known  as  the  crossed  lens,  whose 
radii  of  curvature  are  in  the  proportion  of  one  to  six. 
Spherical  aberration  may  be  corrected  partly  by  a  combina- 
tion of  lenses  and  partly  by  the  use  of  diaphragms,  the  lat- 
ter of  which  exclude  all  but  the  central  rays,  or  all  but  the 
peripheral  rays. 

Chromatic  aberration  arises  from  the  difference  in  the  re- 
frangibilities  of  the  colored  rays  in  the  spectrum,  and  the 
decomposition  of  white  light  into  the  colored  or  spectral 
light,  whenever  it  is  transmitted  through  a  homogeneous 


SPECIALTIES — THE  CAMEEA  AND  LENS. 


35 


transparent  medium  whose  two  surfaces  are  not  parallel. 
But  the  two  surfaces  of  a  lens  are  never  parallel ;  therefore 
every  simple  and  homogeneous  lens  must  decompose  light 
into  the  spectral  colors  of  which  the  violet  on  one  side  is 
much  more  refrangible  than  the  red  on  the  other.  On  this 
account  the  focus  of  the  red  light  will  be  more  remote  from 
the  lens  than  that  of  the  violet  light.  This  sort  of  aberra- 
tion, therefore,  has  the  same  tendency  as  spherical  aberra- 
tion to  convert  points  and  lines  into  circular,  rectangular, 
or  curvilinear  spaces,  with  an  additional  inconvenience  aris- 
ing from  the  different  colors,  which  it  is  well  known  are 
possessed  of  very  different  degrees  of  actinism.  Now, 
when  both  these  causes  of  distortion  and  indistinctness  ex- 
ist in  a  lens  or  in  a  combination  of  lenses,  it  is  not  in  the 
power  or  skill  of  the  photographer  to  obtain  a  well-defined, 
sharp,  and  actinically  well-developed  picture.  Some  sorts 
of  glass  refract  light  more  than  others  ;  again,  some  decom- 
pose light  into  the  spectral  colors  differently,  so  that  the 
angle  between  the  extreme  rays,  the  red  and  the  violet, 
where  the  refracting  angle  of  the  prism  or  lens  is  the  same, 
but  the  material  different,  is  not  a  fixed  quantity.  Com- 
bining these  angular  differences,  the  differences  in  the  re- 
fracting powers  of  transparent  media  and  the  varying  radii 
of  curvature,  mathematicians  are  now  able  to  devise  a  variety 
of  combinations  of  lenses  which  are  practically  free  from  the 
aberrations  in  question.  Generally  crown-glass  and  flint- 
glass  are  combined  in  accordance  with  the  principles  just 
alluded  to.  Such  a  combination  corrects  partially ;  it  is  a 
decided  improvement  over  any  single  lens  as  regards  fine 
definition  ;  but  what  it  gains  in  definition  it  loses  in  magni- 
fying power.  A  triplet,  or  a  combination  of  three  lenses, 
properly  constructed,  is" an  improvement  upon  the  doublet ; 
and  a  pair  of  doublets  whose  radii  and  distances  are  mathe- 
matically and  optically  calculated,  can  be  made  to  produce 
more  correction  than  it  is  possible  to  obtain  from  a  triplet. 
Three  pairs,  too,  will  effect  more  than  two ;  but,  unfortun- 
ately, whatever  is  now  gained  in  focal  sharpness  is  diminished 
in  value  by  the  absorbing  power  of  the  different  lenses  ;  so 
that  when  the  combinations  increase  in  number,  the  light 
which  finally  emerges,  however  much  corrected,  becomes 
more  and  more  actinically  weak.  For  photographical  pur- 
poses, a  pair  of  compound  lenses  can  be  constructed  and 
adjusted  so  as  to  be  practically  perfect.  We  are  indebted 
to  Dolland  for  the  first  achromatic  combination.  Doublets 
and  triplets  are  decidedly  the  best  arrangements  for  land* 


36 


SPECIALTIES — THE  CAMERA  AND  LENS. 


scape  photography ;  whereas  two  pairs  of  doublets,  adjusted 
at  a  given  distance  apart,  or  at  a  variable  distance  apart, 
are  preferred  for  portraiture.  The  nearer  the  pairs  of  com- 
binations approach  each  other,  the  greater  the  magnifying 
power;  the  maximum  power  existing  when  they  are  in  jux- 
taposition. When  a  tube  is  fitted  up  so  that  one  of  the 
combinations  admits  of  motion  by  a  rack  and  pinion,  its  focal 
length  can  be  thus  changed,  and  is  practically  good  within 
certain  limits.  With  such  tubes,  too,  it  becomes  an  easv 
matter  to  adjust  a  pair  of  them  for  stereoscopic  purposes. 

The  following  rules  and  information  will  be  found  useful 
for  ascertaining  the  comparative  value  of  the  different  tubes 
in  the  market. 

To  find  the  Principal  Focus  of  a  Lens, — Fix  the  lens  in  a 
tube  or  aperture  in  the  camera;  then  turning  the  camera 
to  the  moon,  adjust  the  slide  until  the  image  on  the  ground- 
glass  is  perfectly  in  focus ;  measure  the  distance  from  the 
ground-glass  to  the  nearest  surface ;  then  with  a  pair  of  cal- 
lipers take  the  thickness  of  the  lens  and  divide  this  thickness 
by  two ;  now  add  this  half  to  the  first  distance,  which  will 
be  the  focal  distance  exactly  if  the  lens  is  double-convex  and 
its  radii  of  curvature  are  equal.  Proceed  in  like  manner 
with  a  compound  lens ;  the  result  will  be  very  nearly  cor- 
rect. Where  the  tube  contains  two  pairs  of  combinations, 
a  similar  method  may  be  adopted  without  much  error.  In 
speaking  of  the  focal  distance  of  a  lens,  or  of  a  combination, 
it  is  customary  simply  to  measure  the  space  between  the 
ground-glass  and  the  nearest  surface  of  the  last  combina- 
tion, after  focussing  the  moon  or  the  sun. 

To  find  the  JEqui-distant  Conjugate  Foci  of  a  Lens  or 
Combination. — Adjust  the  object,  as,  for  instance,  a  card- 
picture,  in  front  of  the  lens  or  cohibination  in  the  camera, 
until  the  image  on  the  ground-glass  is  of  an  exactly  equal 
size  with  the  object  w^hen  in  perfect  focus.  Measure  the 
distance  from  the  image  to  the  object  and  divide  this  dis- 
tance by  two  ;  the  quotient  will  be  the  quantity  required. 

To  find  the  Comparative  Value  of  Two  Lenses  or  Com- 
binations  which  produce  the  same  Sized  Image  of  an  Object 
at  the  same  Distance. — Take  the  difference  between  the  equi- 
distant conjugate  focus  and  the  principal  focus  of  either  lens ; 
the  smaller  this  difference  the  better  the  lens,  because  the 
focal  depth  or  penetration  is  greater ;  that  is,  objects  farther 
apart  can  be  brought  into  focus  consentaneously  and  with 
more  facility  when  this  difference  is  small  than  when  it  is 
large.    If  this  difference  were  zero,  a  lens  would  be  perfect. 


SPECIALTIES  THE  CAMERA  AND  LENS. 


To  find  the  Magnifying  Power  of  a  Lens  or  Combination. 
— On  a  sheet  of  card-board,  in  the  middle,  construct  a  circle 
one  inch  in  diameter,  for  instance ;  place  this  sheet  on  a 
table.  Insert  the  lens  or  tube  into  a  piece  of  wood  placed 
horizontally  over  the  circle,  and  raise  or  depress  it  by  blocks 
or  books  until  the  circle  is  seen  most  distinctly  when  viewed 
with  one  eye.  Now,  by  a  little  practice,  with  both  eyes 
open,  one  looking  through  the  tube  and  the  other  on  the 
side  upon  the  paper,  marks  can  be  made  on  the  board  at 
the  extremities  of  a  diameter  of  the  magnified  circle ;  be- 
cause the  eye  which  is  free  can,  by  sympathy,  see  the  mag- 
nified image  which  the  other  eye  beholds,  and  the  pencil  at 
the  same  time.  After  this,  measure  the  distance  between 
the  pencil-marks,  and  divide  this  distance  by  the  diameter 
of  the  real  circle  ;  the  quotient  will  indicate  the  number  of 
times  the  image  is  larger  than  the  object,  which  number  is 
the  magnifying  power. 

To  find  the  Comparative  Magnifying  Power  of  Lenses  or 
Combinations. — Measure  the  distance  in  either  between  the 
lens  and  the  ground-glass  when  the  moon  is  in  focus,  or 
measure  the  size  of  the  image  ;  the  greater  this  distance  or 
image,  the  less  the  magnifying  power.  The  quotient  aris- 
ing by  dividing  one  distance  with  the  other  will  give  the 
amount  of  magnifying  poAver  in  favor  of  the  lens,  whose  dis- 
tance is  the  shorter. 

To  find  a  Single  Lens  equ  ivalent  in  Power  to  a  Compound 
Lens. — If  a  compound  lens  and  a  single  lens  be  placed  so 
that  their  centers  are  at  the  same  distance  from  the  moon  or 
a  distant  object,  for  instance ;  then,  if  they  produce  the  same 
sized  picture,  one  will  be  equivalent  to  the  other.  (For 
further  information  vide  chapters  on  Microphotography  and 
Macrophotography.) 

To  ascertain  whether  a  Combination  is  corrected  for 
Spherical  Aberration. — Draw  two  parallel  straight  lines,  ex- 
actly an  inch  apart,  and  two  or  three  inches  long,  on  a  piece 
of  card-board.  Move  the  slide  until  they  are  correctly  in 
focus  on  the  ground-glass,  and  until  the  width  between  the 
lines  is  two  inches.  If  this  distance  remains  the  same,  that 
is,  if  the  lines  do  not  deviate  from  straight  lines  and  from 
parallelism,  the  combination  is  aplanatically  correct ;  if,  on 
the  contrary,  the  images  of  the  straight  lines  are  curves,  the 
spherical  aberration  has  not  been  corrected.  Apply  a  dia- 
phragm of  small  opening  in  front  of  the  combination  ;  it  will 
De  perceived  that  the  curvature  of  the  lines  will  diminish 
as  the  aperture  diminishes.    If  with  a  very  small  aperture 


38 


SPECIALTIES — THE  CAMERA  AND  LENS. 


the  lines  are  still  curved,  the  combination  is  worthless ; 
whereas,  if  the  lens  or  combination  can  be  used  without  a 
diaphragm  and  still  produces  straight  and  parallel  lines  in 
the  images,  such  a  magnifier  will  be  very  valuable. 

To  ascertain  whether  a  Lens  or  Combination  is  corrected 
for  Chromatic  Aberration. — Adjust  the  slide  most  accur- 
ately, so  that  the  image  of  an  object  is  very  clear  and  dis- 
tinct. Next  see  that  the  surface  of  the  collodionized  plate  is 
exactly  coincident  with  the  ground-surface  of  the  glass,  that 
is  to  say,  at  the  same  distance  from  the  nearest  surface  of 
the  lens.  Sensitize  the  collodion  film  and  take  a  picture. 
If,  when  developed  and  fixed,  this  picture  is  as  sharp  and 
well-defined  as  it  was  on  the  ground-glass,  the  lens  is  achro- 
matic ;  if,  on  the  contrary,  the  contrast  between  light  and 
shade  is  imperfect,  and  the  definition  and  sharpness  feeble, 
the  combination  has  been  either  over-corrected,  under-cor- 
rected, or  not  corrected  at  all.  The  actinic  rays  are  on  the  vio- 
let side  whose  refrangibilities  are  greater  than  those  of  the  red 
rays ;  their  focal  distance,  therefore,  is  shorter.  Focus  again, 
and  after  this  has  been  accomplished  draw  the  slide  contain- 
ing the  ground-glass  outward  about  one  sixteenth  part  of  an 
inch,  insert  the  sensitized  plate,  expose,  develop,  and  fix,  as 
before.  If  the  picture  is  better  than  before,  it  shows  that 
the  actinic  focus  is  longer  than  the  luminous,  and  that  the 
combination  has  been  over-corrected.  By  proceeding  in  this 
way,  it  can  be  ascertained  exactly  how  much  the  slide  has  to 
be  drawn  out  in  order  to  produce  a  picture  as  sharp  as  that 
on  the  ground-glass.  After  this  distance  is  found,  the  ground- 
glass  has  to  be  advanced  or  sunk  deeper  in  its  frame  by  this 
amount,  whereby  the  camera  becomes  adjusted  to  the  tube. 
Should  it  happen  that  the  slide  has  to  be  pushed  in  after 
focussing  in  order  to  obtain  sharp  definition  on  the  collodion, 
it  is  an  indication  that  the  lens  is  under-corrected  or  not  cor- 
rected at  all.  Where  a  lens  requires  no  adjustment  of  the 
ground-glass,  it  is  said  to  be  achromatically  correct,  or  that 
the  actinic  and  luminous  foci  are  coincident.  The  value  of 
a  lens  in  this  respect  is  inversely  proportionate  to  the  amount 
of  adjustment  required ;  that  is,  the  greater  the  amount  cf 
adjustment,  the  less  its  value. 

Other  methods  have  been  proposed  to  test  the  coincidence 
of  the  actinic  and  luminous  foci.  One  consists  in  pasting  a 
newspaper  on  a  flat  board,  and  erecting  the  latter  perpen- 
dicular to  the  horizon  and  in  front  of  the  opening  of  the  lens, 
so  that  the  axis  of  the  lens  passes  through  the  center  of  the 
newspaper  and  at  right  angles  to  it.    The  operator  next  ob- 


SPECIALTIES  THE  CAMERA  AND  LENS. 


39 


tains  a  sharp  focus  upon  the  central  parts,  and  afterward  ob- 
tains a  positive  of  the  object.  If  the  central  parts  are  still 
in  focus  in  the  picture,  the  combination  has  been  achromat- 
ically  corrected ;  if  the  parts  intermediate  from  the  center  to 
the  periphery  are  in  focus,  the  lens  has  been  over-corrected  ; 
and  more  so  if  the  marginal  portions  alone  are  in  focus ; 
whereas,  if  the  picture  is  nowhere  sharp,  it  is  probable  the 
lens  has  not  been  sufficiently  or  not  at  all  corrected  for  chro- 
matic aberration. 

A  second  method  is  to  focus  first  in  the  ordinary  way  ; 
then,  placing  a  piece  of  violet-colored  glass  in  front  of  the 
lens,  to  focus  again ;  if  the  two  foci  coincide,  the  actinic  and 
luminous  foci  coincide. 

A  third  method  is  that  proposed  by  Claudet,  which  consists 
in  placing  printed  cards  at  short  distances  apart,  as,  for  in- 
stance, of  one  tenth  of  an  inch,  in  grooves  on  an  inclined 
plane  resting  on  a  table  in  front  of  the  tube.  Let  there  be 
five  cards  so  arranged,  and  focus  upon  the  middle  one.  If 
the  first  or  second  is  in  focus,  the  lens  is  under-corrected ;  if 
the  middle  one  is  sharp,  the  lens  is  unexceptionable  ;  and  if 
the  fourth  or  fifth  is  well  defined,  the  combination  is  over- 
corrected. 

For  an  over-corrected  lens  or  combination  the  ground-glass 
has  to  be  set  back  by  introducing  thin  pieces  of  card-board 
between  it  and  the  ledge  of  the  slide  in  which  it  rests ;  and 
where  the  correction  has  been  defective,  the  glass  has  to  be 
sunk  deeper  as  before  mentioned. 

If  a  combination  has  been  thoroughly  corrected,  I  throw 
aside  the  ordinary  ground-glass  slide  entirely,  and  focus  upon 
a  piece  of  glass  of  the  same  size  as  the  collodionized  plate, 
and  introduced  into  the  self-same  aperture  which  is  to  con- 
tain the  negative.  In  this  way  the  collodion-surface  and  the 
ground-surface  must  necessarily  coincide. 

How  to  buy  a  Good  Lens. — Do  not  purchase  a  second- 
hand tube  of  any  one,  if  you  are  a  beginner  in  the  art  of  pho- 
tography ;  but  throw  yourself  implicitly  and  in  full  confidence 
into  the  hands  of  a  photographic  house  of  decided  reputation, 
who  will  furnish  you  with  a  lens  and  camera  in  perfect  ad- 
justment and  in  working  condition.  The  tubes  manufac- 
tured in  this  country  by  two  or  three  different  firms,  are, not 
inferior  to  the  best  from  abroad ;  and  the  advantage  you 
have  in  dealing  directly  with  them  or  their  immediate  agents 
is,  that  if  by  chance  a  lens  turns  out  in  any  way  defective, 
you  can  immediately  obtain  redress  by  an  exchange.  As 
soon  as  an  operator  is  sufficiently  skilled  in  optics  and  their 


40 


SPECIALTIES  THE  CAMERA  AND  LENS. 


application  to  the  heliographic  art,  he  will  be  in  a  condition 
to  rely  upon  his  own  judgment,  and  to  make  his  purchases 
where  pecuniarily  they  are  the  most  advantageous.  The 
best  criterion  by  which  to  ascertain  whether,  after  purchas- 
ing an  adjusted  tube  and  camera,  the  actinic  and  luminous 
foci  coincide,  is  to  take  the  plate-holder  containing  a  plate  of 
glass  with  the  slide  drawn  and  place  it  upon  a  table,  collo- 
dion side  uppermost ;  by  the  side  of  this  place  the  ground- 
glass  slide  with  the  ground-surface  uppermost.  Placing  a 
rigid  flat  ruler  over  either  of  these,  it  will  be  easy  to  measure 
the  distance  from  each  glass  surface  to  the  edge  of  the  ruler. 
Where  these  two  distances  coincide,  there  has  been  no  need 
of  adjustment ;  and  the  lens  may  be  regarded  as  good.  If 
the  difference  is  well  marked,  I  would  recommend  you  to 
return  the  tube  and  get  a  better. 

Supposing,  furthermore,  lenses  to  be  aplanatic  and  achro- 
matic, there  exist  special  differences  by  which  their  relative 
values  can  be  distinctly  estimated.  The  value  of  such  in- 
struments depends  upon  the  extent  of  picture  in  perfect  de- 
finition which  can  be  obtained  by  them,  with  a  given  open- 
ing, focal  distance,  and  diaphragm,  and  on  the  velocity  with 
which  this  work  can  be  accomplished.  If  of  two  lenses  of 
equal  opening  and  equal  focal  distance,  the  one  will  produce 
as  sharp  and  large  a  picture  without  a  stop  as  the  other 
can  with  a  diaphragm ;  the  former  is  very  much  superior, 
because,  with  much  more  light,  the  operation  of  actinism 
will  be  relatively  quicker.  In  like  manner,  if  of  two  lenses 
whose  three  parts,  as  enumerated  above,  are  all  equal,  but 
the  picture  of  one  is  considerably  larger  than  that  of  the 
other,  and  in  every  respect  as  well  defined,  the  comparative 
value  is  easy  to  determine.  Wherever  this  difference  in  the 
size  of  the  picture  exists,  other  things  remaining  the  same, 
it  will  be  found  that  the  lens  which  produces  the  largei 
picture  will  likewise  comprehend  a  larger  angular  space  con- 
taining objects.  Drawing  imaginary  lines  from  the  two  ex- 
tremities of  the  landscape,  for  instance,  through  the  center 
of  the  lens  or  combination,  to  the  corresponding  extremities 
of  the  picture,  two  isosceles  triangles  are  formed  with  their 
vertical  angle  at  the  center.  This  angle  or  opening  of  the 
two  outside  rays  constitutes  what  is  denominated  the  angu- 
lar aperture  of  the  lens.  The  greater  this  angle,  the  other 
values  remaining  the  same,  the  greater  the  practical  worth 
of  the  lens.  For  the  purposes  of  portraiture,  the  lenses  in 
general  have  but  a  small  angular  aperture,  and  produce  a 
picture  but  little  more  in  diameter  than  half  the  focal  dis- 


SPECIALTIES — THE  CAMERA  AND  LENS.  41 


tance.  The  relation  between  the  opening  of  the  lens,  the 
aperture  in  the  diaphragm,  the  focal  distance  and  the  dia- 
meter of  the  picture,  as  given  in  the  Chimie  Photographique, 
are  as  follows  :  Calling  the  focal  distance  unity,  then  the 
diameter  of  the  lens  will  be  \  of  this  unity,  that  of  the  stop 
TV>  and  that  of  the  picture  f.  If  the  diameter  of  the  dis- 
tinct picture  is  equal  to  the  focal  distance,  the  angular  aper- 
ture will  be  about  53°  ;  and  if  this  angle  be  90°,  the  dia- 
meter of  the  picture  will  be  about  twice  as  great  as  the 
focal  distance.  It  is  asserted  that  the  new  globe-tubes,  the  in- 
vention of  C.  C.  Harrison,  have  an  aperture  of  ninety  degrees, 
and  that  they  are  free  from  spherical  and  chromatic  aberra- 
tion ;  they  will  therefore  be  in  a  condition  to  produce  large 
pictures  with  a  small  focus.  The  only  disadvantages  which 
they  probably  possess  will  be  a  deficiency  of  light,  owing  to 
the  smallness  of  the  aperture  in  the  stops  ;  an  inequality  of 
action  from  the  center  to  the  peripheral  parts  ;  and  the  pro- 
duction of  what  is  denominated  the  "  ghost"  on  the  center 
of  the  picture,  owing  to  reflections  between  the  lenses  of 
the  combination.  For  architectural  and  landscape  photo- 
graphy they  must  be  inestimable,  if  the  assertion  of  their 
merits  is  true. 

The  Arms  in  this  country  that  have  gained  a  well-earned 
reputation  for  the  manufacture  of  portrait,  etc.,  lenses  are 
those  of  C.  C.  Harrison  &  Co.,  and  of  Holmes,  Booth,  and 
Haydens  ;  in  Great  Britain,  those  of  Ross,  Dallmeyer,  Grubb, 
etc. ;  in  France,  of  Jamin,  etc. ;  in  Germany,  of  Voightlseiider, 
etc. 


0 


CHAPTEE  V. 


SPECIALTIES  CONTINUED. — THE  CAMERA. 

The  camera  obscura  was  the  invention  of  Porta,*  a  Nea- 
politan ;  this  instrument  is,  in  fact,  a  miniature  glass-house, 
a  conjugate  glass-house,  which  admits  no  light  but  that  which 
passes  through  the  lens.  The  ground-glass  is  the  screen, 
which  must  be  at  right  angles,  and  slide  at  right  angles  with 
the  axis  of  the  lens.  The  model,  therefore,  or  sitter,  must 
likewise  be  so  arranged  that  the  various  component  parts 
that  have  to  appear  in  the  picture  shall  be  as  much  as  pos- 
sible in  a  plane  perpendicular  to  the  optical  axis.  In  this 
case,  it  becomes  the  duty  of  the  photographic  artist,  as  soon 
as  his  model  is  gracefully  and  compactly  arranged,  to  fix 
upon  the  point  which  is  to  be  the  center  of  the  picture,  as, 
for  instance,  the  eye  of  the  sitter,  then  to  reconnoiter  the 
ground,  and  examine  the  inclination  of  the  different  parts  of 
the  figure  forming  the  visible  surface,  and  to  ascertain  the 
direction  of  a  line  drawn  from  the  eye  at  right  angles  to  this 
surface  ;  now  bring  the  camera,  raise  it  and  incline  it  until 
the  axis  of  the  lens  coincides  with  this  previously  deter- 
mined direction.  In  this  position,  it  will  be  possible  to  ob- 
tain a  picture  in  which  the  different  parts  are  almost  equally 
in  focus.  Before  you  begin  to  obtain  the  focus  on  the 
ground-glass,  fix  the  lens  in  its  brass  slide  in  the  middle  of 
its  motion  by  the  rack  and  pinion.  Next  move  the  bellows- 
slide  of  the  camera  until  the  image  on  the  glass  is  distinct, 
and  clamp  the  slide  ;  finally  obtain  a  sharp  focus  by  means 
of  the  thumb-screw  on  the  pinion-wheel.  With  a  quick 
motion  backward  and  forward  of  the  lens,  the  point  of 
sharpest  definition  can  easily  be  descried  with  the  naked  eye, 
as  long  as  the  image  is  much  smaller  than  the  object ;  but 
in  copying  photographs  or  engravings,  where  the  picture  is 
to  be  of  equal  size  with  the  original,  it  is  not  easy  to  obtain 
the  exact  focus ;  in  this  case  the  microscope  is  called  into 

*  Porta,  Giovanni  Battiste  Delia,  was  born  at  Naples,  in  1 540. 


SPECIALTIES  CONTINUED  THE  CAMEBA. 


43 


requisition.  The  first  thing  to  be  done,  where  this  difficulty 
exists,  is  to  hunt  about  upon  the  original  photograph  or  en- 
graving for  some  distinct  landmark,  as  a  very  minute  circle, 
:>r  a  couple  of  lines  in  apparent  juxtaposition,  or  the  open- 
ing in  the  letter  e  or  0,  or  the  extreme  lines  on  the  sides  of 
a  blade  of  grass  ;  the  space  between  these  will  become  very 
manifest  under  the  microscope,  and  by  a  sweep  of  the  lens 
backward  and  forward,  the  boundary-lines  can  be  designated 
when  most  sharp.  It  requires  much  practice  to  focus  well 
in  copying ;  hence  it  is  that  few  photographers  are  good 
copyists.  The  microscope  suitable  for  such  purposes  may 
be  a  common  magnifying-glass,  the  front  lens  of  one  of  the 
stereoscopic  tubes,  or  a  compound  microscope  of  low  power. 
An  error  in  the  focal  distance  of  one  sixteenth  of  an  inch, 
in  portraiture,  is  scarcely  perceptible  ;  whereas  the  same 
amount  of  error  in  copying  will  produce  a  total  failure  in 
the  negative  or  positive.  In  taking  a  view,  and  in  copy- 
ing, it  is  frequently  a  plan  to  be  recommended,  to  focus  a 
point  midway  between  the  center  of  the  picture  and  the  out- 
side. This  is  said  to  equalize  the  definition ;  it  is  essentially 
a  means  of  dividing  the  error  of  spherical  or  chromatic 
aberration,  where  either  exists.  The  eye  of  the  sitter  may 
regard  some  fixed  point  on  a  level  with  its  direction ;  care 
must  be  taken  that  it  is  neither  raised  nor  depressed  nor  in 
any  way  strained.  By  looking  at  some  point  on  the  camera, 
which  is  situated  in  the  darkest  part  of  the  glass-house,  the 
eyes  will  be  able  to  remain  quite  at  ease,  even  whilst  stead- 
fastly gazing  at  this  point ;  if,  however,  the  sight  were 
directed  to  a  point  brilliantly  lighted,  the  eyelids  would  in- 
voluntarily close,  and  the  pupil  contract,  by  which  the  pic- 
ture would  be  impaired. 

The  photography  of  architecture  and  of  landscapes  re- 
quires  absolutely  that  the  camera  be  horizontal,  and  so  does 
that  of  card-pictures,  when  the  whole  figure  is  compre- 
hended, in  order  to  avoid  the  pyramidal  inclination  of  parts 
which  in  nature  are  parallel.  This  pyramidal  distortion  is 
the  consequence  of  the  obliquity  of  the  rays  as  they  are 
thus  made  to  enter  the  lens,  and  for  which  obliquity  the 
lens  has  not  been  corrected.  On  account  of  the  large  angle 
which  a  card-picture  must  necessarily  comprehend,  a  long- 
focussed  lens  is  preferred,  much  longer  than  is  required  for 
taking  a  portrait  at  the  same  distance.  It  is  a  frequent  oc- 
currence to  those  who  occupy  themselves  with  out-door  pho- 
tography not  to  be  able  to  comprehend  certain  very  desir- 
able elevations  within  the  compass  allotted  to  the  photo- 


SPECIALTIES  CONTINUED  THE  CAMERA. 


graph  without  inclining  the  tube  upward ;  but  the  tube 
must  remain  horizontal ;  therefore  the  only  alternative  re- 
maining is  to  raise  the  camera  upon  a  platform  or  to  place  it 
on  a  window-sill,  on  the  roof  of  a  house,  on  the  branch  of  a 
tree,  or  on  the  spokes  of  two  ladders,  tied  or  hinged  at  the 
top,  and  with  the  feet  drawn  out  so  as  to  form  a  large  base 
between  them.  Lenses  with  large  aperture  are  exceedingly 
useful  in  such  cases,  as,  for  instance,  in  taking  views  of 
churches,  public  buildings,  etc.,  from  the  opposite  side  of  the 
street. .  The  great  desideratum  has  been  to  find  a  lens  of  short 
focus  and  large  angle  for  such  sort  of  work,  which  can  not  be 
performed  with  lenses  of  long  focus  and  small  aperture. 

If  the  objects  in  the  foreground  of  a  view,  as  is  the  case 
with  a  stereograph,  are  to  be  the  principal  items  of  atten- 
tion, the  lens  will  have  to  be  focussed  either  upon  the  cen- 
tral object  or  upon  one  intermediate  between  the  center  and 
the  edge.  In  this  case,  unless  the  difference  between  the 
focus  of  parallel  rays  and  the  focus  at  an  infinite  distance  be 
exceedingly  small,  almost  all  remote  objects  will  be  slightly 
out  of  focus,  and  the  picture  in  the  distant  background  will 
be  defective.  To  counteract  this  effect,  a  much  larger  lens 
is  employed,  which  is  carried  to  some  distance  from  the 
principal  objects,  until  the  picture  be  of  the  same  size  as 
was  intended  to  be  taken  with  the  lens  of  shorter  focus.  The 
camera,  too,  in  such  a  case,  must  be  raised  above  the  hori- 
zon, but  focussed  parallel  to  it.  The  scenery  in  close  prox- 
imity can  be  thus  excluded,  and  the  distant  view  will  be 
nearly  equally  well  defined  and  in  true  perspective.  A 
small  view  taken  in  this  manner  can  be  enlarged  afterward 
either  into  a  negative  or  positive,  as  may  be  required,  by  the 
method  which  is  fully  explained  hereafter. 

There  are  certain  rules  to  be  observed  in  field-photography 
in  reference  to  the  light,  as  in  room-photography. 

The  first  is,  not  to  place  the  axis  of  the  camera  in  the 
same  straight  line  with  the  sun  and  the  object.  This  means 
that  a  picture  is  not  to  be  taken  in  the  direction  of  the  sun's 
rays,  where  the  front  and  central  objects  are  equally  illu- 
mined, and  consequently  must  be  very  flat  in  the  photo- 
graph ;  it  would  be  equally  absurd  to  attempt  a  picture  in 
the  shade,  whilst  the  sun  is  shining,  as  it  were,  into  the 
camera  through  the  lens. 

An  inclination  of  the  axis  of  the  camera  with  the  direc- 
tion of  the  sun's  light,  to  the  amount  of  forty-five  degrees, 
will  produce  an  agreeable  contrast  of  light  and  shade.  It 
is  very  possible  and  very  probable  that  such  an  illumina- 


SPECIALTIES  CONTINUED — THE  CAMERA.  45 

tion  from  the  unobscured  rays  will  produce  too  strong 
a  contrast,  and  thus  give  rise  to  a  very  hard  picture.  The 
best  effects  are  attained  when  the  sun  is  obscured  by  a 
white  cloud ;  the  lights  and  shades  still  exist  with  the  addi- 
tion of  decided  middle  tints,  giving  the  photograph  the  ap- 
pearance of  an  artistic  production. 

With  these  recommendations  in  view,  the  photographer 
must  visit  the  ground  previously  to  his  taking  a  picture,  in 
order  to  ascertain  at  what  time  of  the  day  the  light  falls 
upon  it,  or  can  fall  upon  it,  so  as  to  produce  the  best  photo- 
graphic illumination  ;  this  sort  of  proceeding  distinguishes 
the  artist  from  the  operator,  and  gives  the  same  distinction 
to  his  work.  It  may  happen  that  the  principal  object  in  a 
landscape,  which  it  is  required  to  photograph,  is  so  situated 
as  not  to  receive  the  direct  light  of  the  sun,  as  is  the  case 
with  many  northern  aspects.  The  artist,  in  such  a  case,  will 
have  to  wait  for  a  cloudy  day,  when  the  direct  light  of  the 
sun  can  produce  no  real  shadows,  and  when  perhaps  a  white 
cloud  in  the  north-east  or  north-west  may  be  found  to  make 
sufficient  contrast. 

Cameras  for  lenses  of  short  focus  can  be  roughly  adjusted 
to  focus  by  means  of  the  bellows-slide,  and  afterward  finely 
adjusted  with  the  thumb-screw  on  the  lens ;  but  when  the 
focus  is  long,  the  thumb-screw  is  useless,  unless  attached  to 
a  long  lever,  as  was  formerly  used  in  the  Lucernal  micro- 
scope; in  such  cameras,  the  bellows-slide  has  a  rough  or 
quick  motion,  and  a  slow  or  fine  motion  by  means  of  a 
thumb-screw  in  front  of  the  operator  or  on  the  posterior 
part  of  the  slide.  Such  cameras,  too,  by  reason  of  their 
length,  have  to  be  supported  on  two  camera-stands,  in  order 
to  make  them  rigid. 


CHAPTER  VI. 


SPECIALTIES  CONTINUED.  DARK-ROOM. 

The  chamber  intended  for  all  operations  of  sensitizing, 
commonly  called  the  Dark-Room,  ought  to  lie  contiguous  to 
and  open  into  the  common  operating  or  work-room  of  the 
photographer ;  and  both  these  rooms  ought  to  open  di- 
rectly into  the  glass-house.  As  before  recommended,  they 
can  be  constructed  on  the  northern  aspect  of  the  gallery, 
each  being  seven  and  a  half  feet  wide — that  is,  half  the  width 
of  the  glass-room — and  about  ten  or  twelve  feet  long.  The 
work-room  may  be  that  on  the  left,  whilst  the  remaining  cham- 
ber is  on  the  right,  with  a  door  in  the  middle  of  the  parti- 
tion between  them.  A  single  pane  of  orange-yellow  colored 
glass  on  the  northern  end  is  all  that  is  needed  ;  this  window 
may  be  about  four  feet  from  the  ground,  in  order  that,  when 
the  operator  is  standing,  the  light  whilst  developing  may 
come  from  below  and  through  the  negative.  This  mode  of 
admitting  light  permits  the  progress  of  development  to  be 
distinctly  watched  much  more  effectively  than  by  reflected 
light.  The  elevation  of  the  pane  of  glass  above  the  floor 
must  be  regulated  in  accordance  with  the  stature  of  the 
operator  and  his  habits  of  standing  or  bending  during  the 
process,  so  that  sometimes  an  elevation  of  two  or  three  feet 
above  the  floor  of  the  room  will  be  found  sufficient.  The 
size  of  the  pane  will  be  adequately  large,  if  its  sides  are 
eight  inches  by  six,  and  a  dark-colored  curtain  is  adjusted 
over  this,  so  as  to  render  the  room  almost  dark  in  case  of 
need.  On  the  north,  east,  and  south  sides  a  shelf  is  con- 
structed twelve  inches  wide,  and  three  feet  from  the  floor. 
In  the  north-west  corner  the  pail  or  barrel  is  placed  to  con- 
tain water  for  washing  the  negatives  ;  this  pail  or  barrel  it> 
supplied  with  a  brass  stop-cock,  such  as  is  used  for  beer  or 
wine  ;  beneath  the  stop-cock,  and  on  the  floor,  is  placed  the 
large  wash-tub  or  sink  for  containing  or  carrying  off  the  re- 
fuse dirty  water.  Beneath  the  north-west  and  the  north-east 
corner  there  will  be  found  abundance  of  space  for  the  gutta- 


SPECIALTIES  CONTINUED — DARK-ROOM.  4^ 

percha  developing  and  fixing  dishes,  as  also  for  the  respective 
solutions  used  in  these  processes,  and  for  intensifying,  as,  for 
instance,  protosulphate  of  iron,  pyrogallic  acid,  cyanide  of 
potassium,  hyposulphite  of  soda,  solution  of  iodine  in  iodide 
of  potassium,  tincture  of  iodine,  nitrate  of  silver,  bichloride 
of  mercury,  and  sulphide  of  potassium.  Each  of  these  so- 
lutions must  be  legibly  labeled,  always  placed  in  the  same 
position,  and  always  carefully  corked.  As  regards  the  solu- 
tion of  the  sulphide  of  potassium,  the  necessity  for  accurate 
closing  of  the  bottle  which  contains  it  is  absolute,  because 
the  fumes  of  hydrosulphuric  acid,  if  allowed  to  escape  into 
the  room,  would  decompose  the  sensitizing-bath,  and  injure 
the  prints  and  negatives.  As  soon  as  a  negative  or  positive 
is  complete,  the  developing  and  fixing  solutions  are  poured 
back  into  their  respective  vials.  Care  must  be  taken  here 
also  not  to  interchange  dishes  ;  for  the  cyanide  of  potassium 
decomposes  the  iron-salt  into  what  soon  becomes  Prussian 
blue  by  oxidation  of  the  iron,  and  thus  renders  it  a  difficult 
task  to  clean  the  dish  afterward.  The  first  things  in  order 
on  the  eastern  shelf  are  the  plate-holders,  leaning  in  their  re- 
spective places  against  the  wall ;  after  this  comes  the  sen- 
sitizing-bath, on  an  inclined  frame  fixed  upon  the  shelf.  The 
inclination  may  be  about  fifteen  degrees  from  the  perpendic- 
ular ;  if  it  were  more  than  this,  the  light  particles  of  the 
undissolved  iodide  of  silver,  and  of  other  insoluble  sub- 
stances, would  be  apt  to  settle  upon  the  tender  surface  of  the 
collodion,  and  give  rise  to  apertures  in  the  negative.  To 
avoid  this  calamity  of  photographers,  it  is  preferable  to  have 
some  arrangement  by  which  the  collodionized  plate  can  be 
introduced  into  the  sensitizing-bath  with  its  collodion  sur- 
face downward.  For  this  purpose  flat  dishes  are  used  with 
a  glass  or  porcelain  ledge  on  the  right  side  to  support  one 
end  of  the  plate,  whilst  the  other  end  rests  on  the  bottom 
of  the  dish  on  the  left  side.  In  this  way  the  left  end  of  the 
collodionized  plate  is  introduced  first  into  the  bath,  whilst 
the  right  end  is  gradually  and  quickly  lowered,  by  means  of 
a  silver  or  glass  hook,  until  it  comes  in  contact  with  the  ele- 
vated ledge  which  is  to  support  it.  The  plate  is  to  be  com- 
pletely covered  with  the  nitrate  of  silver  when  thus  lowered 
upon  its  support,  which  need  not  be  more  than  a  quarter  of 
an  inch  above  the  bottom  of  the  dish.  Naturally,  when  the 
plate  is  in  this  position,  the  collodion  is  nowhere  in  contact 
with  the  vessel  which  contains  it,  excepting  at  the  upper 
and  lower  edges.  By  making  the  above-mentioned  ledge 
still  more  shallow,  a  very  small  quantity  of  the  silver  solu« 


48 


SPECIALTIES  CONTINUED — DARK-ROOM. 


tion  will  suffice  to  cover  the  plate,  and  the  solution  can  be 
filtered,  if  necessary,  after  each  operation ;  whereby  there 
can  be  but  small  risk  of  any  damage  from  the  deposition  of 
particles  of  undissolved  matter  upon  the  film  of  collodion. 
In  this  country,  the  vertical  or  slightly  inclined  sensitizing- 
baths  are  preferred,  and  consequently  in  most  general  use  ; 
in  France  and  Germany,  the  horizontal  baths  are  frequently 
to  be  met  •  with,  and  are  certainly  to  be  recommended  in 
order  to  avoid  the  trouble  above  alluded  to. 

To  the  right  of  the  silver-bath  for  collodion-plates  is  the 
appropriate  place  of  the  horizontal  dish  to  contain  the  sen- 
sitizing solution  for  the  chloridized  paper.  This  dish  will 
have  a  capacity  to  meet  the  requisitions  of  the  establish- 
ment, and  may  contain  a  whole  sheet,  a  half-sheet,  or  even 
less,  as  the  case  may  be.  On  a  small  shelf  two  feet  above 
this  dish  are  placed,  in  separate  bottles,  the  plain  silver  and 
the  ammonio-nitrate  of  silver  solutions,  a  small  filtering- 
stand  and  funnel,  ammonia,  alcohol,  and  distilled  water :  and 
running  from  the  dish  to  the  southern  side  is  constructed  an 
inclined  plane  with  a  semicircular  groove  covered  or  lined 
with  plates  of  glass  or  porcelain,  each  one  overlapping  its 
fellow  like  tiles.  The  first  one  just  projects  over  the  edge 
of  the  dish.  This  grooved  inclined  plane  is  screwed  to  the 
eastern  side  of  the  room,  and  being  thus  tiled,  is  situated  in 
the  right  position  for  receiving  the  droppings  of  nitrate  of 
silver  from  the  sensitized  sheets  when  removed  from  the 
dish,  and  attached  by  pins  through  an  upper  angle  to  a  soft 
wooden  slip  immediately  above.  The  first  sheet  that  is 
taken  from  the  bath  is  fixed  at  the  most  distant  point,  and 
so  that  the  lowest  angle  is  just  in  contact  with  the  upper- 
most inclined  glass  tile ;  the  next  is  pinned  close  to  it,  until 
the  row  is  complete.  If  the  lower  corners  or  angles  of  the 
silvered  paper  touch  the  glass,  the  superfluous  fluid  will 
easily  flow  off  and  down  the  inclined  plane  into  the  dish ;  if 
the  corners  curl  up,  it  will  then  be  necessary,  with  a  small 
pad  of  cotton-wool  or  a  glass  rod,  to  remove  the  accumu- 
lated solution,  by  bringing  the  corner  in  contact  witfr  the 
grooved  channel.  By  this  arrangement  the  photographer  is 
able  to  economize  his  time  and  his  solution.  As  soon  as  one 
row  is  thus  filled  with  sensitized  papers,  those  first  pinned 
up  will  probably  be  sufficiently  dry  for  removal  to  another 
slip  situated  on  the  southern  side  of  the  dark-chamber,  thus 
making  room  for  a  fresh  quantity  of  papers. 

The  semicircular  grooves  of  glass  can  be  manufactured  as 
follows :  Take,  for  instance,  a  piece  of  iron  plate  about  fif- 


SPECIALTIES  CONTINUED — DAKK-KOOM. 


49 


teen  inches  long  and  two  inches  wide,  and  get  it  hammered 
longitudinally  into  a  hollow  groove ;  next  cut  up  slips  of 
glass  of  the  same  length,  and  about  an  inch  and  a  half  wide. 
Place  one  of  these  slips  of  glass  in  the  iron  channel  so  that 
it  lies  uniformly  in  the  middle.  Now  heat  the  iron  carefully 
red-hot,  when  it  will  be  found  that  the  glass  will  soften, 
sink,  and  assume  the  shape  of  the  mould.  When  this  has 
succeeded,  allow  the  iron  to  cool  gradually,  in  order  that 
the  glass  may  be  properly  annealed.  By  arranging  these 
cylindrical  glasses  so  that  they  overlap  each  other  about 
half  an  inch,  in  the  form  of  tiles,  there  is  no  need  of  apply- 
ing cement. 

WORK-ROOM. 

The  collodion  can  be  kept  on  a  small  shelf  in  the  dark- 
room, close  by  the  door,  in  a  very  convenient  place  to  seize 
when  occasion  requires.  With  this  convenience,  the  plates 
are  flowed  in  the  doorway  between  the  two  rooms.  At  the 
north  end  of  the  work-room  there  is  a  good,  large  window, 
with  the  lower  part  about  two  feet  from  the  floor,  flush  with 
the  upper  part  of  a  shelf  or  table  constructed  right  across, 
from  side  to  side.  On  the  sides  of  the  window-frame,  on 
nails  or  hooks,  hang  the  various-sized  mats  for  cutting  albu- 
men, etc.,  papers  or  photographs,  as  well  as  the  different- 
sized  plate-holders,  diaphragms,  pliers,  scissors,  diamonds, 
rulers,  brushes,  pencils,  etc.,  used  in  mounting,  printing,  etc. 
On  the  left  side  of  the  table,  on  small  shelves,  are  kept  acetic 
acid,  nitric  acid,  hydrochloric  acid,  sulphuric  acid,  protosul- 
phate  of  iron  in  crystals,  distilled  or  rain-water,  citric  acid, 
pyrogallic  acid,  alcohol,  pestle  and  mortar,  stirring-rods  of 
glass,  weights  and  scales,  graduated  measure  for  drachms 
and  ounces,  another  for  minims  and  drachms,  cyanide  of 
potassium,  hyposulphite  of  soda,  gun-cotton,  iodide  and  bro- 
mide of  cadmium,  iodide  and  bromide  of  ammonium,  nitrate 
of  silver,  ammonia,  chloride  of  ammonium,  gum-arabic,  ge- 
latine, solution  of  gum-arabic,  etc.,  brush,  spatula,  and  bur- 
nishing-tool,  carbonate  of  lime,  chlorinetted  lime,  acetate 
of  soda,  phosphate  of  soda,  iodine,  iodide  of  potassium, 
bromide  of  potassium,  bichromate  of  potassa,  and  other 
chemical  materials  for  experimentation.  The  preceding  ar- 
ticles have  to  be  arranged  on  narrow  shelves  in  the  order  in 
which  they  can  be  most  conveniently  laid  hold  of,  accord- 
ing to  their  respective  merits  as  necessary  or  accessory  in- 
gredients. On  the  right  side  of  the  window  arrange  the 
various-sized  glasses  already  cut,  bath  for  negatives  and 


50 


SPECIALTIES  CONTINUED  DARK-ROOM. 


positives,  the  patent  plate-holder  or  vice  for  cleaning  glass 
plates,  rotten-stone,  alcohol,  solution  of  salts  of  tartar,  dilute 
solution  of  nitric  acid,  cotton  or  linen  rags,  patches  of  Can- 
ton-flannel, silk  cloths,  broad  camel-hair  pencil  for  dusting  off 
particles  or  fibers  from  the  polished  glasses,  triangular  file, 
alcohol-lamp,  shell-lac  for  mending  the  glass-corners,  box  of 
pins,  box  of  tacks,  small  hammer,  large  and  thick  glass 
plate  for  cutting  out  photographs,  etc.,  scale  and  compasses, 
vignette-glasses,  the  different-sized  printing-frames,  varnish, 
mats,  preservers,  cases,  transfer-liquid,  leather,  black  paper 
or  velvet,  etc.,  mounts  of  various  sizes. 

The  sides  of  this  room  are  furnished  with  wooden  strips 
to  which  photographs  can  be  attached  by  pins  m  order  to 
dry  them  after  fixation  and  washing.  The  toning  and  fix- 
ing dishes  are  situated  on  the  shelf  on  the  west  side ;  as  are 
also  the  chloride  of  gold, .  test-paper,  nitrate  of  uranium, 
.acetate  and  phosphate  of  soda,  rain-water,  alcohol,  and 
hyposulphite  of  soda.  Beneath  the  shelf  place  the  tubs  for 
washing  prints.  In  drawers  preserve  the  different  sorts  of 
paper  in  use.  Have  one  drawer  for  dry  but  uncut  positives, 
one  for  the  cut  positives,  one  for  uncut  stereographs,  one  for  the 
right  stereographs  and  one  for  the  left,  one  for  card-pictures 
not  cut,  and  one  for  the  prepared  card-pictures.  One  writ- 
ing-desk near  the  door  and  between  the  door  and  the  win- 
dow, for  containing  the  day-book,  etc.  Photographic  stock 
can  be  stored  away  on  shelves  on  the  southern  end  and  on 
the  sides  of  this  room.  Both  these  rooms  are  to  be  supplied 
with  stoves  or  other  means  of  warmth  and  ventilation.  On 
the  entrance-door  affix  the  sign  forbidding  all  intrusion. 
Keep  all  visitors  in  the  antechamber,  which  must  be  made 
comfortable,  and  somewhat  artistically  furnished  for  their 
reception.  The  photographer  can  not  perform  his  duties 
with  ease  if  crowded  with  inquisitive,  meddling,  and  talking 
parties ;  the  lenses  do  not  operate  well  if  the  air  is  saturated 
with  vapor,  and  the  health  is  impaired  in  the  midst  of  the 
mixed  effluvia  arising  from  degenerate  lungs. 


CHAPTER  VII. 


COLLODION". 

In  1851  Legray  first  suggested  the  application  of  collodion 
for  the  receptacle  of  the  photographic  picture ;  and  in  the 
same  year  Messrs.  Archer  and  Fry  published  a  detailed  ac- 
count of  the  practical  mode  of  its  application  Collodion  is 
a  solution  of  gun-cotton  in  ether  and  alcohol ;  and  gun-cot- 
ton, of  which  there  are  several  varieties,  is  cotton  or  linen 
fiber  (that  is,  cellulose  or  lignine)  altered  by  combination 
with  peroxide  of  nitrogen  and  probably  with  nitric  acid. 
Cotton  consists  chemically  of  carbon,  hydrogen,  and  oxygen ; 
whilst  gun-cotton  contains  an  additional  element,  namely, 
nitrogen,  which  communicates  explosive  tendencies  to  several 
of  the  metalloids.  The  altered  cotton  employed  for  photo- 
graphic purposes  is  not  the  same  as  gun-cotton  proper ;  in 
the  first  place  it  is  not  so  explosive ;  it  is,  secondly,  almost 
perfectly  soluble  in  alcohol  and  ether,  which  is  not  the  case 
with  gun-cotton.  It  is  denominated  pyroxyline.  Pyroxy- 
line  is  soluble  also  in  acetic  ether.  When  this  soluble  cot- 
ton is  dissolved  in  a  mixture  of  ether  and  alcohol,  and  after- 
ward poured  upon  a  piece  of  glass,  it  leaves  on  evaporation, 
when  of  a  normal  condition,  a  transparent  film ;  whereas 
gun-cotton  so  dissolved,  or  xyloidine,  (another  form  of  altered 
cotton,)  leaves  an  opaque  film  after  evaporation. 

Cotton  or  ligneous  fiber  is  transformed  into  pyroxyline  by 
immersing  it  in  a  mixture  of  nitric  acid  and  sulphuric  acid  ; 
the  latter  seems  necessary  only  to  concentrate  the  nitric  acid ; 
for  neither  sulphur  nor  any  of  its  oxides  are  found  in  pyroxy- 
line by  analysis.  This,  although  the  accepted  theory,  is  not 
satisfactory,  because  it  is  found  necessary  to  add  water  to 
certain  specimens  of  nitro-sulphuric  acid.  Another  reason 
for  the  use  of  sulphuric  acid  arises  from  the  fact  that  pyroxy- 
line is  soluble  into  a  gelatinous  form  in  nitric  acid,  but  not 
in  the  mixture  of  nitric  and  sulphuric  acids.  Gun-cotton 
may  be  precipitated  from  its  ethereal  and  alcoholic  solution 
into  a  fibrinous  mass  like  the  original,  almost.    This  curious 


52 


COLLODION. 


fact  exhibits  quite  an  analogy  between  solutions  of  salts  and 
the  mineral  kingdom,  and  the  gelatinous  solutions  in  the 
organic  kingdom.  In  the  former  the  precipitate  is  either 
amorphous  or  crystalline,  as  in  chloride  of  silver  and  car- 
bozotate  of  potassa ;  whilst  in  organic  solutions  the  precip- 
itated ultimate  atoms  seem  to  exist,  even  in  solution,  in  the 
form  of  fiber.  This  peculiar  fibrinous  deposit  is  thrown 
down  by  adding  water  to  the  mixed  ethereal  and  alcoholic 
solution  of  pyroxyline,  because  this  substance  is  insoluble  in 
water.  For  this  reason  the  necessity  of  using  only  concen- 
trated ether  and  alcohol  is  apparent ;  another  deduction  is 
equally  apparent  from  this  circumstance,  which  consists  in 
the  employment  of  such  iodizing  materials  in  the  prepara- 
tion of  sensitive  collodion,  as  are  soluble  in  ether  and  alco- 
hol, and  in  discarding  those  which  are  soluble  principally  in 
water,  or  only  partially  in  ether  and  alcohol.  Collodion 
containing  a  small  proportion  of  water  is  thick  and  flows 
unevenly,  and  when  dry  is  not  quite  transparent ;  whilst  the 
film  from  anhydrous  collodion  is  very  thin,  transparent,  and 
uniform,  and  flows  on  the  surface  of  glass  very  easily. 

Preparation  of  Pyroxyline. — For  this  purpose  the  finest 
cotton  or  the  best  Swedish  filtering-paper,  or  old  white  cotton 
rags  are  procured.  These  materials,  especially  the  first,  are 
not  quite  pure  ;  a  sort  of  resinous  cement  adheres  with  great 
tenacity  to  its  fibers,  and  must  first  be  dissolved  before  the 
cotton  is  fit  for  transformation  into  pyroxyline.  The  cotton 
is  therefore  boiled  in  a  solution  of  carbonate  of  potassa  in 
the  following  proportion :  take  one  hundred  parts  of  rain  • 
water,  two  parts  of  cotton,  and  one  of  carbonate  of  potassa. 
These  materials  are  maintained  at  a  boiling  temperature  for 
a  few  hours,  after  which  the  cotton  is  taken  out  and  thor- 
oughly washed  in  several  waters,  and  then  left  in  clean 
rain-water  for  at  least  twenty-four  hours,  stirring  the  same 
from  time  to  time,  until  every  trace  of  the  alkali  is  removed. 
It  is  then  taken  out,  pressed,  and  dried  in  thin  layers  spread 
upon  clean  sheets  of  paper  in  the  sun  or  on  a  steam-bath. 
Care  must  be  taken  that  all  moisture  be  entirely  expelled. 
In  this  condition  it  is  ready  for  the  action  of  nitric  acid. 
Certain  rules  have  to  be  minutely  observed  in  regard  to  the 
temperature  of  the  nitric  acid,  the  quantity  of  water  which 
it  contains,  the  length  of  time  of  immersion,  and  the  inti- 
mate mixture  of  the  ingredients ;  for  as  these  conditions  vary 
so  will  the  pyroxyline.  If,  for  instance,  the  acids  are  too 
strong,  or  the  temperature  too  low,  the  pyroxyline  will  be 
much  heavier  than  the  weight  of  the  cotton  used,  without 


COLLODION. 


53 


apparently  having  undergone  any  other  outward  change. 
Such  gun-cotton  will  produce  a  thick  and  gelatinous  collo 
dion,  giving  rise  to  streaks  in  the  film.  If,  on  the  contrary, 
the  resulting  pyroxyline  is  less  in  weight  than  the  cotton 
introduced,  or  about  equal  to  it,  this  indicates  that  the  acids 
are  too  weak  or  the  temperature  too  high,  whereby  a  portion 
of  the  pyroxyline  is  dissolved.  Such  a  species  of  gun-cc,vton 
is  not  wholly  soluble  in  a  mixture  of  ether  and  alcohol ;  it 
yields,  however,  a  collodion  which  flows  easily  over  the 
plate,  is  very  adhesive  to  the  glass,  and  yields  a  soft  nega- 
tive. Any  little  particles  of  dust  that  may  fall  on  the  plate 
are  liable  to  produce  with  this  collodion  transparent  specks 
on  the  positive  or  negative.  The  rule,  therefore,  on  the 
whole  is  to  steer  between  these  two  results,  in  order  to  ob- 
tain a  pyroxyline  in  which  the  cotton  fiber  shows  an  incipi- 
ent gelatinization  in  the  acids.  When  the  operation  is  suc- 
cessful, the  weight  of  the  dry  pyroxyline  will  be  somewhere 
about  twenty-five  per  cent  heavier  than  the  cotton  from 
which  it  was  formed. 

No.  1.  Formula  for  the  Preparation  of  Pyroxyline. 
Commercial  sulphuric  acid,  spec,  grav.,  1.843  at  60  Fahr.,.  .24  fluid  ounces. 


The  vessels  used  in  the  preparation  of  pyroxyline  may  be 
large  porcelain  or  glass  evaporating-dishes,  sitting  closely  in 
the  cover  of  a  water-bath,  maintained  at  a  temperature  of 
150°  Fahrenheit.  Each  dish  is  furnished  with  a  pane  of 
glass,  fitting  upon  it  as  a  lid  or  cover.  Let  the  water-bath 
be  first  raised  to  the  indicated  temperature  ;  then  pour  the 
sulphuric  acid  into  one  of  the  dishes,  add  to  this  the  water,  and 
mix  intimately  by  stirring  with  a  glass  rod  with  a  rounded 
end ;  finally  pour  in  the  nitric  acid,  and  perform  the  same 
operation  to  insure  an  intimate  mixture.  The  temperature 
of  this  mixture  will  rise  from  15  to  20  degrees  above  the 
point  required.  Remove  the  dish,  therefore,  from  the  bath 
until  the  temperature  falls  to  150°.  The  temperature  can 
be  lowered  by  stirring  the  mixture  with  cold  stirring-rods  or 
spatulas  of  porcelain  or  glass.  Whilst  the  acids  are  cooling 
the  cotton  can  be  divided  into  about  a  dozen  lots,  and  each 
lot  must  be  gently  separated  into  a  loose  condition.  As 
soon  as  the  proper  temperature  has  been  attained,  the  dish 
is  reinstated  in  its  position  in  the  water-bath,  and  the  cotton 
is  introduced  one  lot  at  a  time,  so  that  each  is  carefully 


Commercial  nitric  acid, 

Water,  

Cotton,  


1.45T  " 


u 


1  ounce. 


54 


COLLODION. 


pressed  down  beneath  the  surface  by  the  glass  rod.  As 
soon  as  all  the  cotton  has  been  introduced  and  completely 
covered  by  the  acid  mixture,  the  lid  is  placed,  on  the  dish 
for  six  or  eight  minutes. 

The  thermometer  used  on  such  occasions  for  ascertaining 
the  temperature  of  the  water  or  mixed  acids,  must  be  strong- 
ly made,  so  that  the  bulb  can  be  moved  about  in  the  fluid 
with  some  degree  of  briskness  without  any  liability  to  break ; 
it  is  furnished  with  a  hinged  back,  which  allows  the  lower 
portion  to  be  reflected  on  itself,  and  the  bulb  and  the  lower 
part  of  the  stem  to  be  exposed.  Such  thermometers  are 
manufactured  for  the  chemist,  and  can  be  purchased  at  the 
photographic  establishments. 

The  acids  are  now  poured  into  another  dish  close  by, 
allowing  the  largest  portion  to  drain  off,  and  preventing  the 
cotton  from  falling  out  at  the  same  time  by  the  cover  which 
is  retained  in  its  place.  The  dish  containing  the  pyroxyline 
is  then  quickly  immersed  in  a  large  tub  of  water,  and  the 
cotton  is  well  stirred  about  so  as  to  part  with  the  largest 
portion  of  its  acidity ;  it  is  then  taken  out  with  a  pair  of 
glass  rods  and  plunged  into  fresh  water  in  another  tub,  and 
again  thoroughly  washed.  After  this  operation  the  pyroxy- 
line is  placed  in  a  wooden  chamber  through  which  a  current 
of  water  is  kept  running  for  twenty-four  hours  or  more,  or 
at  least  until  every  trace  of  acidity  has  been  removed.  Dur- 
ing this  time  the  agglutinated  or  adherent  portions  are  care- 
fully separated,  so  that  the  stream  of  water  can  more  easily 
act  upon  each  fiber.  When  blue  litmus  paper  is  no  longer 
turned  red  by  the  water  as  it  proceeds  from  the  cotton,  the 
latter  is  taken  out,  again  carefully  separated  and  placed  in 
thin  patches  on  sheets  of  paper  in  the  sun  to  dry ;  or  it  may 
be  dried  on  zinc  plates,  being  part  of  a  hot-water  bath, 
whose  temperature  is  maintained  at  about  120°  Fahrenheit. 
At  this  temperature  pyroxyline  will  not  explode.  In  the 
hot  days  of  summer,  however,  it  can  be  dried  quite  effica- 
ciously when  placed  out  in  the  sun. 

Pyroxyline,  when  exposed  to  the  air,  absorbs  moisture ;  it 
undergoes  decomposition,  too,  in  an  air-tight  vessel,  if  light 
reaches  it ;  the  products  of  decomposition  being  nitric  acid, 
peroxide  of  nitrogen,  and  probably  other  compounds.  It 
has  not  yet  been  thoroughly  ascertained  by  what  means  it 
can  be  preserved  in  a  normal  condition  permanently ;  ab- 
sence of  moisture  and  of  light  have  been  found  to  assist  in 
this  preservation. 


COLLODION. 


55 


If  a  specimen  of  pyroxyline  by  keeping  manifests  an  acid 
reaction,  it  is  advisable  to  wash  the  cotton  in  several  waters, 
as  before,  and  again  to  dry  it.  To  neutralize  the  cotton  by 
an  alkali,  or  a  carbonated  alkali,  is  scarcely  to  be  recom- 
mended,* because  they  both  have  a  tendency  to  decompose 
it ;  and  especially  if  any  trace  of  these  should  be  left  in  the 
fiber,  decomposition  is  likely  to  ensue  in  the  drying. 

No.  2.  Formula  for  the  Preparation  of  Pyroxyline. 


By  Weight. 

Commercial  sulphuric  acid,  spec,  grav.,  1.843,  at  60°  Fahr.,  18  ounces, 

Commercial  nitric  acid,         "       "      1.43,    "  "     "   14  " 

Cotton,   2  " 

Proceed  with  these  ingredients  in  all  other  respects  as 
with  those  in  Formula  No.  1. 

No.  3.  Formula  for  the  Preparation  of  Pyroxyline. 

Commercial  sulphuric  acid,  40  ounces, 

Pure  nitrate  of  potassa,  20  " 

Cotton,   1  ounce. 


As  soon  as  the  mixture  of  acid  and  nitre  has  been  thor- 
oughly mixed,  and  almost  cool,  the  cotton  is  introduced  in 
small  portions  and  well  stirred.  In  about  a  quarter  of  an 
hour  the  whole  mixture  is  thrown  into  a  large  tub  full  of 
water ;  in  this  way  the  pyroxyline  is  freed  as  much  as  possi- 
ble from  the  acid  ;  after  this  it  is  washed  in  warm  water, 
and  finally  in  a  running  stream,  as  in  Formula  ISTo.  1. 

No.  4.  Formula  for  the  Preparation  of  Pyroxyline. 

DisderVs  Pyroxyline. 

Sulphuric  acid,  4000  grains. 

Pulverized  pure  nitrate  of  potassa,  2000  44 

Place  these  in  a  glass  vessel  provided  with  a  close-fitting 
cover,  and  stir  them  intimately  together  with  a  glass  rod. 
Next  add  150  grains  of  fine  cotton-wool,  in  small  flocks  at  a 
time,  and  immerse  them  thoroughly  with  the  glass  rod. 
When  all  the  cotton  has  been  introduced,  close  the  vessel 
and  set  it  aside  for  ten  or  fifteen  minutes.  After  this,  the 
pyroxyline  is  withdrawn  by  means  of  a  pair  of  glass  rods, 
and  well  washed,  as  before  recommended,  and  dried. 

In  all  these  formulas  the  acids,  when  once  used,  can  not 
be  employed  a  second  time ;  by  distillation,  the  nitric  acid 


56 


COLLODION. 


that  has  not  been  decomposed  might  be  obtained  and  used 
over  again,  if  other  combinations  and  decompositions  did 
not  result  from  the  application  of  so  high  a  temperature. 
In  general  the  mixture  is  regarded  as  useless,  and  thrown 
away. 


CHAPTER  VIII. 


ETHER    AND  ALCOHOL. 

The  next  ingredients  employed  in  the  manufacture  of 
plain  or  normal  collodion  are  alcohol  and  ether.  Both 
these  substances  belong  to  a  group  of  hydrocarbons  whose 
basic  compound  radical,  although  hypothetical,  is  denomin- 
ated ethyle,  consisting  of  four  equivalents  of  carbon  com- 
bined with  five  of  hydrogen,  and  represented  in  symbols  by 
C4  H5.  Ether  is  the  oxide  of  this  base,  and  alcohol  the  hy- 
drated  oxide ;  that  is,  chemically  regarded,  the  only  differ- 
ence between  ether  and  alcohol  is,  that  the  latter  contains 
one  equivalent  of  water,  constitutionally  combined,  which  is 
wranting  in  ether.  The  hypothetical  compound  base,  ethyle, 
enters  into  combination  with  several  of  the  alkaloids  and 
acids,  giving  rise  to  distinct  chemical  combinations.  This 
fact  will  lead  us  to  seek  a  clue  for  various  untoward  and, 
as  yet,  unaccountable  phenomena  in  the  constitution  of  sensi- 
tized collodion,  and  its  frequent  want  of  permanency. 

Ethyle  Group. 

Ethyle,  Symbol  Ae,  C4  H5.      Cyanide  of  ethyle,  Ae  Cy. 

Oxide  of  ethyle,  (ether,)  Ae  0.        Nitrate  of  the  oxide  of  ethyle,.  .Ae  0,  N05. 

Hydrated  oxide  of  ethyle,  (alcohol,).  Ae  0,  HO.  Nitrite  of  the  oxide  of  ethyle,.  .Ae  0,  N0.3. 

Bromide  of  ethyle,  Ae  Br.       Oxalate  of  the  oxide  of  ethyle,  .Ae  0,  C2  63. 

Chloride  of  ethyle,  Ae  CI.       Hydride  of  ethyle,  Ae  H. 

Iodide  of  ethyle,  Ae  I.         Zinc  ethyle,   Ae  Zn,  etc. 

Some  of  the  compounds  of  the  ethyle  series  are  crystalliz- 
able  salts  ;  but  the  most  of  them  are  volatile  aromatic  fluids, 
denominated  ethers. 

Although  an  equivalent  of  water  is  the  only  difference 
between  alcohol  and  ether,  yet  no  direct  means  have  yet 
been  discovered  whereby  an  atom  of  water  can  be  so  com- 
bined with  ether  as  to  form  alcohol,  nor  abstracted  from  al- 
cohol constitutionally  so  as  to  leave  ether.  It  is  supposed, 
therefore,  that  the  elements  that  enter  into  the  formation  of 
ether,  and  water  and  ether,  owe  their  difference  to  a  differ- 
ence in  the  grouping  of  the  elementary  atoms. 


63 


ETHER  AND  ALCOHOL. 


ETHER. 

Ether,  sometimes  denominated,  but  very  wrongly,  sul- 
phuric ether,  is  obtained  by  decomposing  alcohol  by  means 
of  sulphuric  acid.  One  method  consists  in  the  distillation 
of  equal  weights  of  rectified  alcohol  (spec.  grav.  .835)  and 
sulphuric  acid.  As  soon  as  ebullition  commences,  a  color- 
less and  highly  volatile  liquid  passes  over  and  is  condensed 
into  a  receiver  surrounded  with  ice  or  snow.  This  method 
is  far  from  being  a  profitable  one  ;  for  at  a  temperature  be- 
low 260°  Fahr.  alcohol  distils  over;  and,  if  the  heat  be  greater 
than  310°,  another  of  the  numerous  hydrocarbons,  olefiant 
gas,  is  generated,  together  with  other  gaseous  and  liquid 
bodies.  By  a  second  method  the  sulphuric  acid  is  main- 
tained at  a  temperature  of  about  300°  Fahr.,  and  a  stream 
of  alcohol  is  made  to  enter  the  acid  gradually.  In  this  way 
a  large  quantity  of  alcohol  becomes  converted  into  ether. 
There  are  two  stages  in  the  preparation  of  ether ;  by  one  an 
impure  and  crude  ether  is  the  result ;  by  the  latter  the  ether 
is  rectified.    The  minutiae  are  as  follows : 

Take  of  alcohol  four  pints  ;  sulphuric  acid,  one  pint ; 
potassa,  six  drachms;  distilled  water,  three  fluid  ounces. 
Add  gradually  fourteen  fluid  ounces  of  the  acid  to  two  pints 
of  the  alcohol  in  a  tubulated  retort,  and  shake  frequently  in 
order  to  produce  an  intimate  mixture.  Connect  the  retort 
when  placed  on  a  sand-bath  with  a  proper  condensing  ap- 
paratus, furnished  with  a  long  connecting-tube,  so  as  to  re- 
move the  vapors,  if  any  should  escape,  as  far  as  possible 
from  the  flame.  Explosions  are  very  apt  to  take  place  in 
the  preparation  of  ether,  unless  great  caution  be  taken. 
The  temperature  is  now  raised  quickly  until  ebullition  com- 
mences. As  soon  as  half  a  pint  of  ether  has  distilled  over, 
the  remainder  of  the  alcohol  previously  mixed  with  two 
fluid  ounces  of  the  acid  is  allowed  to  enter  gradually  through 
the  tubulated  aperture  by  means  of  a  tube  dipping  beneath 
the  mixture  in  the  retort,  and  in  quantity  as  near  as  can  be 
equal  to  that  which  distills  over.  In  this  way  continue  the 
distillation  until  about  three  pints  have  passed  over  into  the 
condenser. 

The  product  thus  obtained  contains  sulphurous  acid,  sul- 
phuric acid,  sulphovinic  acid,  and  other  impurities.  By 
rectification  most  of  these  are  removed  as  follows  : 

Add  to  the  ethereal  contents  in  the  condenser  the  solution 
of  the  potassa  in  the  distilled  water,  and  shake  them  fre- 
quently during  the  twenty-four  hours  they  are  kept  together 


ETHER  AND  ALCOHOL. 


59 


in  a  stoppered  bottle.  After  subsidence  separate  the  super 
natant  ethereal  solution  by  means  of  a  syringe,  and  distill  off 
two  pints  of  this  solution  at  a  low  and  gentle  heat.  The 
specific  gravity  at  this  stage  will  be  about  .750.  By  further 
rectification  over  newly  burnt  quicklime  and  chloride  of  cal- 
cium, ether  may  be  obtained  of  a  specific  gravity  of  .720,  or 
even  lower.  When  perfectly  pure  its  specific  gravity  is  .713, 
and  it  boils  at  95°.  The  sulphuric  ether  of  commerce  is  not 
sufficiently  concentrated  for  photographic  purposes;  and 
none  can  be  relied  upon  excepting  that  which  is  obtained 
direct  from  establishments  that  prepare  chemical  ingredients 
for  the  photographer.  When  the  specific  gravity  is  .720, 
ether  boils  at  98°  ;  this  is  the  kind  which  is  generally  used 
in  the  preparation  of  collodion.  When  too  long  kept  it  un- 
dergoes decomposition,  being  converted  partially  into  acetic 
acid.  It  is  a  very  important  solvent  of  oils,  resins,  and  al- 
kaloids, and  certain  metalloids,  as  iodine,  bromine,  sulphur, 
and  phosphorus.  It  does  not  dissolve  potassa  and  soda,  a 
very  distinct  characteristic  from  alcohol.  It  unites  in  all 
proportions  with  alcohol  and  with  one  tenth  its  volume  of 
water.  The  impurities,  as  before  mentioned,  are  acids,  al- 
cohol, water,  and  oil  of  wine.  The  presence  of  acids  are 
shown  by  litmus  ;  alcohol  combines  with  water  when  added 
in  excess,  and  settles  and  forms  the  lower  stratum ;  by  de- 
cantation  the  upper  stratum  is  removed,  which  now  contains 
one  tenth  its  weight  of  water  ;  water  is  removed  by  distilla- 
tion from  fresh  chloride  of  calcium ;  the  acids  by  distillation 
from  lime  or  potassa ;  the  oil  of  wine  is  shown  by  the  pro- 
duction of  a  milkiness  when  mixed  with  water. 


ALCOHOL, 

Alcohol  is  the  rectified  spirit  of  wine  of  the  specific  gravi- 
ty of  0.835,  containing  eighty-five  parts  of  anhydrous  alco- 
hol and  fifteen  of  water.  When  pure  and  anhydrous  it  is 
the  hydrated  oxide  of  ethyle,  (Ae  O,  HO.)  It  contains  six 
equivalents  of  hydrogen,  four  of  carbon,  and  two  of  oxygen== 
H6  C4  02.  All  saccharine  substances  undergoing  vinous  fer- 
mentation give  rise  to  the  vapors  of  alcohol,  which  by  dis- 
tillation are  obtained  in  a  separate  and  more  concentrated 
form.  By  the  vinous  fermentation  sugar  is  converted  wholly 
into  alcohol  and  carbonic  acid  ;  and  it  is  only  from  sugar,  or 
substances  which  by  chemical  processes  are  converted  into 
sugar,  that  the  vinous  exhalation  can  be  obtained.  The  or- 
dinary alcohol  of  commerce  is  not  sufficiently  concentrated 


60 


ETHER  AND  ALCOHOL. 


for  the  purposes  of  the  photographer,  because  the  water 
which  it  contains  would  precipitate  a  solution  of  pyroxyline, 
or  produce  an  opaque  solution.  Like  ether,  therefore,  it  has 
to  undergo  a  process  of  concentration.  Whisky  is  the  spirit 
from  which  the  first  alcohol  is  obtained,  which  contains 
water,  a  peculiar  oil,  and  extractive  matter.  By  distilling  a 
hundred  gallons  of  whisky,  between  fifty  and  sixty  gallons 
of  alcohol  are  received  in  the  condenser  of  a  specific  gravity 
of  0.835.  By  a  second  distillation,  taking  care  to  collect 
only  the  first  portions  and  cautiously  managing  the  heat,  so 
as  not  to  allow  it  to  rise  to  the  temperature  of  boiling  water, 
alcohol  may  be  obtained  of  a  specific  gravity  of  0.825,  which 
is  the  lightest  spirit  that  can  be  received  by  ordinary  dis- 
tillation. At  this  stage  it  contains  eleven  per  cent  of  water 
and  some  small  portions  of  fusel  oil. 

The  process  by  which  most  of  the  remaining  water  is 
separated  from  the  alcohol  is  as  follows  : 

Take  one  gallon  of  the  alcohol  of  commerce ;  chloride  of 
calcium,  (freshly  made,)  one  pound.  Throw  the  chloride 
into  the  alcohol  and,  as  soon  as  it  is  dissolved,  distill  off 
seven  pints  and  five  fluid  ounces.  Or,  take  of  rectified 
spirit  one  pint^  (imp.  meas. ;)  lime,  eighteen  ounces.  Break 
the  lime  into  small  fragments,  mix  with  the  alcohol  in  a  re- 
tort properly  connected,  and  expose  the  mixture  to  a  gentle 
heat  until  the  lime  begins  to  slake ;  then  withdraw  the  heat 
until  the  slaking  is  finished.  Now  raise  the  heat  gently  and 
distill  off  seventeen  fluid  ounces.  Alcohol  thus  obtained  will 
have  a  density,  when  the  operation  is  carefully  managed,  of 
0.796. 

Neither  of  the  preceding  fluids,  taken  separately,  dissolves 
pyroxyline,  a  mixture  of  the  two  is  required  to  perform  this 
operation ;  the  proportion  in  which  they  exist  in  this  mix- 
ture, in  order  to  attain  to  the  maximum  degree  of  photo- 
graphic excellence,  is  a  problem  which  has  not  yet  been 
absolutely  solved.  When  there  is  a  large  excess  of  ether 
over  the  alcohol,  the  former  menstruum  will  easily  dissolve 
from  one  to  one  and  a  half  per  cent  of  the  prepared  cot- 
ton ;  and  this  proportion  will  scarcely  exceed,  under  the 
most  favorable  conditions,  from  two  to  three  per  cent  with- 
out producing  a  precipitate  in  the  solution.  On  the  con- 
trary, if  the  alcohol,  in  its  purest  state,  exists  in  the  mix- 
ture in  greater  quantity  than  the  ether,  three  per  cent  of 
pyroxyline  is  easily  dissolved,  producing  a  collodion  of  the 
proper  consistency;  the  mixture,  however,  will  dissolve 


ETHER  AND  ALCOHOL. 


61 


from  eight  to  ten  per  cent  without  producing  any  deposit  in 
the  collodion. 

The  property  of  ether  in  collodion  is  to  communicate  te- 
nacity to  the  film,  which,  owing  to  the  excess  of  this  fluid, 
frequently  peels  off  from  the  glass  in  one  adherent  sheet ; 
beside  this,  ether  is  more  liable  to  decomposition  than  alco- 
hol, and  is  perhaps  one  of  the  causes  of  the  want  of  perma- 
nency in  collodion,  although  most  probably  pyroxyline  is  the 
principal  cause.  This  want  of  stability,  even  in  normal  col- 
lodion, is  increased  by  the  quantity  of  air  contained  in  the 
same  vessels,  giving  rise  to  an  ethereal  effluvia  which  it  did 
not  possess  before.  This  decomposition  is  much  more  rapid 
when  the  collodion  is  exposed  to  light. 

Decomposition  of  Collodion. — The  decomposition  of  nor 
mal  or  plain  collodion  is  a  fact  that  can  easily  be  verified ; 
but  experience  shows  also  that  the  iodides  and  bromides 
when  dissolved  in  pure  alcohol  and  ether  are  not  decom- 
posed, or  at  any  event  in  a  very  trifling  degree,  when  pro- 
perly protected  in  accurately  closed  bottles  ;  the  fluid  does 
not  change  color  materially,  nor  does  it  show  the  presence 
either  of  free  iodine  or  bromine  ;  furthermore  the  solutions 
in  question,  when  kept  for  any  length  of  time,  produce  the 
same  sensitive  effects  on  plain  collodion  as  if  they  were 
freshly  made.  The  decomposition  in  collodion  does  not 
seem,  therefore,  to  be  superinduced  by  ether,  alcohol,  the 
iodides,  or  the  bromides ;  for  each,  taken  separately  or  in 
combination,  when  pure  and  properly  protected,  is  not  liable 
to  any  perceptible  decomposition.  But  Van  Monckhoven 
maintains,  and  all  photographers  are  aware  of  the  fact,  that 
there  is  a  very  perceptible  difference  between  freshly-made 
plain  collodion  and  old  plain  collodion.  The  difference  is 
this  :  if  a  plate  be  coated  in  newly-made  plain  collodion  and 
then  immersed  in  a  solution  of  nitrate  of  silver  and  exposed 
before  an  object,  and  afterward  submitted  to  the  action  of 
the  developing  fluid,  no  traces  of  the  picture  will  appear ;  on 
the  contrary,  if  the  plain  collodion  be  old,  and  a  plate  be 
treated  with  this  as  in  the  preceding  case,  the  film  will  be 
whitened  by  the  sensitizing  solution,  and  will  be  sensitive  to 
the  action  of  light  when  exposed  before  an  object,  and  will 
yield  a  picture.  A  second  difference  is  this :  the  collodion, 
before  thick  and  consistent,  becomes  thinner  and  exhales  an 
odor  of  nitric  ether  as  it  grows  older. 

Such  being  the  case,  it  seems  evident  that  the  pyroxyline 
is  the  cause  of  the  decomposition,  or  that  the  pyroxyline 


62 


ETHER  AND  ALCOHOL. 


contains  sometimes  extraneous  matter  that  produces  this  de* 
composition ;  and  when  the  change  has  once  set  in,  the  new- 
ly formed  bodies  may  react  upon  the  iodides  or  bromides 
when  introduced,  and  tend  to  produce  a  variety  of  decom- 
positions according  to  the  facility  or  difficulty  with  which 
they  undergo  change. 

But  the  next  question  is :  What  are  the  differences  be- 
tween freshly-made  iodized  collodion  and  an  iodized  collo- 
dion that  has  been  kept  long  ?    They  are  as  follows  : 

Firstly.  New  collodion  is  more  sensitive  to  light  than  old 
collodion. 

Secondly.  Although  more  sensitive,  it  produces  images 
which  are  much  less  intense  than  those  produced  by  old  col- 
lodion, that  is,  the  shadows  are  not  so  deep  or  black.  The 
images  are  mere  surface-pictures  when  developed  with  the 
sulphate  of  the  protoxide  of  iron. 

Thirdly.  If  the  plates  be  washed  after  sensitizing,  (in  the 
dry  process,)  when  freshly-made  collodion  is  used,  no  image 
will  appear ;  on  the  contrary,  with  old  collodion  the  washing 
does  not  prevent  the  picture  from  appearing. 

Fourthly.  The  shadows  of  the  picture  developed  by  the 
protosulphate  of  iron  are  entirely  soluble  in  nitric  acid  when 
a  freshly-made  collodion  is  used ;  and  are  not  entirely  solu- 
ble with  an  old  collodion. 

Fifthly.  New  collodion  is  colorless,  or  nearly  so ;  whereas 
old  collodion  sometimes  is  as  deeply  red  as  a  strong  solution 
of  burnt  sugar. 

Sixthly.  New  collodion  has  the  odor  only  of  alcohol  and 
ether  ;  but  old  collodion  has  a  peculiar  ethereal  smell  resem- 
bling that  of  nitric  ether  and  aldehyde. 

We  are  indebted  to  Van  Monckhoven  for  the  summation 
of  these  differences  in  juxtaposition,  and  many  photographers 
will  recognize  the  truth  of  them. 

The  third  question  to  be  asked  is  then  the  following: 
What  substance  in  solution  will  communicate  to  recently 
prepared  iodized  collodion  the  properties  of  old  collodion  ? 
Hardwich  says  that  grape-sugar,  glycyrrhizine,  and  nitro- 
glucose  will  render  fresh  collodion  much  more  intense,  but 
that  they  diminish  its  sensitiveness.  Such  is  also  the  action 
of  the  substance,  be  it  what  it  may,  contained  in  altered 
collodion,  it  renders  collodion  more  intense  but  less  sensi- 
tive. 

Furthermore  Hardwich  remarks,  that,  if  these  substances 
be  employed  to  increase  the  intensity  of  the  shadows  in  the 


ETHER  AND  ALCOHOL. 


63 


image,  they  ought  to  be  added  cautiously  because  they  de- 
teriorate from  the  keeping  properties.  But  nitro-glucose  is 
said  to  be  an  impurity  in  pyroxyline ;  it  is  analogous  in 
several  respects  to  pyroxyline  ;  and  it  is  prepared  with  sul- 
.  phuric  acid,  nitric  acid,  and  sugar /  but  lignine  or  cellulose 
yields  sugar  when  treated  with  sulphuric  or  nitric  acid , 
hence  in  the  preparation  of  pyroxyline  grape-sugar  is  formed 
at  the  same  time,  and  by  the  further  action  of  the  acids, 
nitro-glucose  is  produced.  That  there  exists  a  duplex  com- 
pound in  collodion  may  be  shown  by  adding  water  to  it ;  a 
precipitate  will  be  formed,  of  which  one  part  is  fibrous  and 
the  other  gelatinous. 

But  the  identity  between  the  unknown  substance  and  ni- 
tro-glucose is  apparently  shown  by  the  identity  of  proper- 
ties. If  nitro-glucose  be  dissolved  in  alcohol,  it  forms  a 
colorless  solution  with  an  odor  of  alcohol,  which  has  no  effect 
at  this  stage  on  collodion,  nor  on  an  alcoholic  solution  of 
nitrate  of  silver ;  but,  after  the  expiration  of  a  few  days,  it 
assumes  a  rose-colored  tinge  and  the  odor  peculiar  to  old  col- 
lodion ;  furthermore,  at  this  second  stage,  it  now  communi- 
cates to  fresh  collodion  all  the  properties  of  old  collodion, 
and  forms  a  precipitate  in  nitrate  of  silver  in  alcohol.  Van 
Monckhoven  in  addition  has  convinced  himself  that  the  pre- 
cipitate formed  in  old  collodion  by  an  alcoholic  solution  of 
nitrate  of  silver  is  six  times  as  bulky  as  that  which  would 
be  the  result  from  the  iodide  of  silver,  and  that  its  proper- 
ties were  the  same  as  those  in  the  precipitate  formed  by 
mixing  the  rose-colored  nitro-glucose  with  alcoholic  nitrate 
of  silver. 

Preparation  of  Glycyrrhizine. — This  substance  is  obtained 
by  boiling  liquorice-root  in  water  for  some  time,  and  adding 
sulphuric  acid  to  the  concentrated  syrup.  A  white  precipi- 
tate is  formed,  containing  glycyrrhizine,  albumen  and  sul- 
phuric acid.  The  albumen  is  removed  by  washing  the  pre- 
cipitate, first  in  acid- water,  then  in  water,  and  afterward  by 
solution  in  alcohol.  Carbonate  of  potash  is  then  added  to 
decompose  the  alcoholic  solution,  and  to  precipitate  the  sul- 
phuric acid.  By  evap orating  the  liquid,  glycyrrhizine  re- 
mains as  a  yellow,  transparent  mass. 

Preparation  of  Nitro-glucose. — Add  one  ounce  of  pow- 
dered sugar  to  a  mixture  of  two  fluid  ounces  of  sulphuric 
acid,  one  of  nitric  acid.  Stir  the  mixture  for  a  few  minutes 
with  a  glass  rod  ;  a  tenacious  mass  may  thus  be  collected 
from  the  fluid,  and  washed  in  warm  water  by  kneading  it 
until  every  trace  of  acid  is  removed. 


64 


ETHER  AND  ALCOHOL. 


Collodion  iodized  with  the  ammonium  salt  is  the  least 
stable  ;  whilst  a  cadmium  collodion  is  the  most  permanent. 
Collodion  in  which  the  alcohol  is  in  larger  abundance  than 
the  ether  is  more  stable,  and  at  the  same  time  more  fluid ;  it 
adheres  well  to  the  glass,  forms  no  ridges  in  flowing,  and  is 
in  fact  quite  structureless. 


CHAPTEE  IX. 


COLLODION  SENSITIZERS  —  IODIDES  AND  BROMIDES. 

The  salts  employed  for  sensitizing  plain  collodion  for  the 
reception  of  the  actinic  impression,  are  the  iodides  and  bro- 
mides of  different  metals,  as  of  potassium,  sodium,  ammo- 
nium, lithium,  zinc,  iron,  calcium,  cadmium,  etc. 

Iodides  and  bromides,  which  are  soluble  in  ether  and  al- 
cohol, can  alone  be  employed  in  the  preparation  of  sensitized 
collodion,  in  order  to  produce,  by  decomposition  in  and  on 
the  film,  an  iodide  and  a  bromide  of  silver,  which  are  insolu- 
ble. In  so  extensive  a  choice  of  materials  it  is  a  difficult 
matter  to  collect  all  the  advantages  of  a  given  iodide  or  bro- 
mide over  its  neighbors ;  so  that  it  has  not  yet  been  decided 
which  is  the  most  appropriate  iodide  or  bromide. 

If  each  soluble  iodide  or  bromide  were  equally  applicable 
in  a  photographic  sense,  then  the  choice  would  be  influ- 
enced by  pecuniary  considerations  of  cost  and  the  quantities 
required ;  and  if  by  weight  the  iodides  and  bromides  were 
equal  in  price,  the  selection  would  fall  upon  that  iodide  and 
bromide  whose  chemical  equivalent  is  the  least ;  for  the  less 
the  combining  proportion  of  a  given  chemical  substance,  the 
less  the  quantity  required  to  produce  a  given  effect.  Guided 
by  this  consideration  of  the  subject,  the  iodide  and  bromide 
of  lithium  would  claim  our  first  attention ;  after  lithium 
come  magnesium,  ammonium,  calcium,  sodium,  iron,  zinc, 
potassium,  cadmium,  etc.  The  solubility  of  the  respective 
iodides  and  bromides  in  a  mixture  of  ether  and  alcohol  will 
naturally  form  a  second  consideration  ;  and,  thirdly,  a  very 
important  property  must  have  its  due  weight  in  the  scales, 
and  that  is  the  stability  of  the  given  salt  in  the  ethereal  solu- 
tion. The  alkaline  iodides  and  bromides  are  all  soluble,  so 
that  lithium  stands,  perhaps,  quite  as  high  as  the  rest  in  this 
respect.  In  absolute  alcohol  the  iodide  of  potassium  is  not 
soluble  to  the  same  extent  as  iodide  of  ammonium.  The  lat- 
ter iodide  is  the  most  easily  decomposed.  On  this  account 
it  is  regarded  as  a  more  sensitive  iodizer;  it  is  also  quicker; 


66       COLLODION  SENSITIZERS — IODIDES  AND  BROMIDES. 

but  on  the  same  account  it  is  unstable  and  undergoes  spon- 
taneous decomposition.  The  iodide  of  ammonium,  as  well 
as  that  of  potassium,  is  very  capricious. 

The  bromide  of  silver  is  sensitive  to  light  as  well  as  the 
iodide  and  the  chloride  ;  but  the  spectral  rays  have  not  the 
same  influence  on  either  of  these  three  salts.  The  actinic 
impression  on  the  iodide  and  bromide  of  silver  is  invisible  or 
latent,  and  requires  the  aid  of  some  developing  agent  to 
make  manifest  the  effect  of  light;  whilst  the  impression 
made  on  the  chloride  of  silver  becomes  manifest  in  propor- 
tion to  the  intensity  and  duration  of  light. 

The  photographed  image  ef  the  solar  spectrum  is  much 
broader  on  the  bromide  of  silver  film,  than  on  the  iodide 
film.  In  the  former  case,  the  violet,  the  indigo,  the  blue, 
and  partially  the  green  produce  actinic  action ;  whilst  in  the 
latter  the  blue  part  is  but  partially  represented.  Equal  por- 
tions on  the  violet  side  and  external  to  the  violet  color  pro- 
duce an  equal  impression  on  either  of  the  films.  The  greater 
capacity  of  the  bromized  film  has  induced  photographers  to 
attribute  to  bromine  qualities  specially  adapted  to  land- 
scape-photography, where  the  greens  occupy  so  large  a  space 
By  the  introduction  of  the  bromides  into  collodion,  together 
with  the  iodides,  much  discussion  has  arisen  to  determine 
the  precise  action  of  the  former.  Certain  collodions  with 
certain  baths  are  acknowledged  to  undergo  an  improvement 
when  a  bromide  is  a  part  of  the  sensitizer ;  the  picture  is 
softened,  that  is,  the  middle  tints  are  more  pronounced,  or 
the  lights  and  shades  more  agreeably  graded  with  the  bromo- 
iodizer,  than  with  the  simple  iodizer.  On  this  account,  pro- 
bably, bromides  have  been  regarded  by  many  as  accelera- 
tors, or  substances  which  render  collodion  more  sensitive  to 
light.  On  this  ground  alone  the  deduction  would  be  false. 
The  capacity  for  comprehending  a  greater  range  of  colors  is 
possessed  by  the  bromo-iodized  collodions.  This,  perhaps,  is 
the  only  true  and  legitimate  deduction  that  can  be  drawn  in 
the  case ;  they  are  considered  by  very  high  authority,  on  the 
contrary,  as  deduced  from  experiments  carefully  conducted, 
to  be  retarders  of  the  actinic  action.  In  consequence  of  the 
greater  comprehensiveness,  as  regards  colors,  of  the  bro- 
mides over  the  iodides,  it  may  be  concluded,  that  there  are 
very  few  cases  in  Avhich  the  bromo-iodized  collodion  can  not 
be  appropriately  preferred  to  the  simply  iodized  collodion  ; 
the  exceptions  being  the  copying  of  engravings,  plain  or  un- 
colored  photographs,  maps,  letter-press  printing,  etc.,  where 


COLLODION"  SENSITIZERS  IODIDES  AND  BROMIDES.  67 

the  iodized  collodion  alone  possesses  all  the  capacity  re- 
quired. 

A  peculiarity  has  been  discovered  in  reference  to  iodized 
collodion.  Some  sorts  of  collodion  are  suitedfor  one  iodizer, 
and  sonie  for  another.  As  a  general  rule,  a  cadmium  iodide 
glutinizes  collodion ;  whereas  an  alkaline  iodide  liquefies  it. 
The  natural  deduction  from  these  circumstances  is  this :  a 
glutinous  or  tenacious  collodion  is  suited  for  sensitizing  with 
iodide  of  ammonium,  or  iodide  of  potassium ;  for  it  becomes 
thereby  less  tenacious,  and  flows  better.  Such  collodion 
soon  attains  its  maximum  amount  of  sensitiveness,  and  al- 
most with  the  same  facility  begins  to  deteriorate ;  it  is  very 
unstable,  and  not  permanent  in  any  degree  of  sensitiveness. 
On  the  other  hand  an  alcohol  collodion,  which  is  in  a  con- 
dition to  flow  easily,  is,  in  fact,  thin  and  liquid,  can  be  ren- 
dered more  glutinous  by  a  cadmium  iodide.  Collodion  thus 
iodized  is  much  more  stable  than  when  iodized  with  the 
alkaline  iodides,  but  it  attains  its  maximum  degree  of  sensi- 
tiveness very  slowly,  that  is,  it  takes  a  longer  time  to  ripen 
than  the  first-mentioned  collodion ;  but  when  ripe,  it  retains 
its  sensitiveness  much  longer,  is  in  fact  a  stable  collodion. 
Coupling  these  two  facts  together,  attempts  have  been  made 
to  combine  the  iodide  of  cadmium  with  an  alkaline  iodide  in 
such  proportions  as  to  comprehend  the  peculiar  advantages 
of  either,  that  is,  the  stability  and  permanency  of  the  one 
with  the  quick  sensitiveness  of  the  other,  and  the  mutual 
tempering  of  either  toward  a  medium  glutinosity  or  lique- 
faction. The  result  of  such  experiments  indicates  that  the 
cadmium  salt  must  exceed  the  alkaline  salt  in  quantity.  As 
soon  as  the  highest  degree  of  sensitiveness  and  stability  can 
be  established  by  means  of  the  iodides  alone,  it  remains  then 
to  combine  with  these  a  certain  proportion  of  a  bromide  to 
communicate  to  the  collodion  a  greater  capacity  for  colors. 
Notwithstanding  that  this  is,  in  my  opinion,  the  view  we 
have  to  take  of  the  matter,  it  must  be  confessed  that  the 
best  working  quantities  of  the  iodides,  or  of  the  bromo- 
iodides  have  not  yet  been  satisfactorily  determined.  The 
difficulty  that  stands  in  the  way  of  this  determination  is  in- 
creased by  the  peculiar  condition  of  the  nitrate  of  silver 
bath,  whether  it  be  acid,  neutral  or  alkaline ;  and  further- 
more whether  it  be  rendered  acid  by  nitric  acid  or  acetic 
acid ;  or  whether  it  contain  carbonate  of  soda  or  acetate  of 
soda.  A  cadmium  iodized,  or  bromo-iodized  collodion  sensi- 
tized in  a  bath  of  nitrate  of  silver  rendered  slightly  acid 
with  nitric  acid,  produces  irreproachable  pictures,  but  not 


68       COLLODION  SENSITIZERS — IODIDES  AND  BllOMIDES. 

more  rapidly  than  a  bath  containing  acetic  acid,  acetate  of 
soda,  or  carbonate  of  soda,  when  these  happen  to  be  in  a 
happy  mood;  but  the  latter  are  very  unstable,  whilst  the 
former  remains  for  a  long  time  constant,  and  is  regarded  ac- 
cordingly the  proper  bath  for  the  cadmium  collodion.  It 
must  not  be  forgotten  that  acids  are  retarders  of  sensitive- 
ness, and  that  consequently  a  bath  that  yields  a  picture  with- 
out spots,  stains,  or  fogginess  is  preferable  in  the  ratio  as  it 
approaches  neutrality.  A  bath  containing  either  acetate  of 
soda  or  carbonate  of  soda  is,  when  in  its  best  condition,  an 
accelerator  ;  but  it  is  very  unstable,  deteriorates  very  quick- 
ly, and  at  present  no  means  are  known  to  rectify  the  evil 
and  preserve  or  restore  the  sensitiveness. 

The  iodides  and  bromides  most  generally  employed  by 
the  photographer  are  those  of  lithium,  potassium,  sodium, 
ammonium,  cadmium,  and  silver. 


CHAPTER  X. 


PREPARATION   OF  THE  IODIDES. 

Several  of  the  iodides  are  formed  by  the  direct  contact  of 
the  elements,  as,  for  instance,  the  iodide  of  iron  and  the 
iodide  of  phosphorus.  Others  by  double  decomposition,  as 
iodide  of  silver  from  a  soluble  iodide  and  nitrate  of  silver. 
And,  finally,  others  are  obtained  by  combining  chemical 
equivalents  of  hydriodic  acid  with  the  carbonates  of  the 
bases  required,  as,  for  example,  iodide  of  potassium  from 
hydriodic  acid  and  carbonate  of  potassa,  iodide  of  barium 
from  hydriodic  acid  and  carbonate  of  baryta,  etc.  Iodine 
or  hydriodic  acid  is  the  material  from  which  the  iodides  may 
be  and  are  prepared. 

Iodine. 

Symbol,  I.    Chemical  Equivalent,  127y7;  Specific  Gravity,  4.948. 

Iodine  was  discovered  in  1812,  by  Courtois,  a  chemical 
manufacturer  in  Paris.  This  substance  exists  in  nature  com- 
bined with  metals,  such  as  calcium,  magnesium,  and  sodium ; 
and  these  are  found  in  many  saline  springs  and  mineral  waters, 
as  also  in  sea-water.  These  salts  are  absorbed  by  several 
marine  plants  and  animals ;  and  it  is  from  such  plants  that 
iodine  is  obtained  in  considerable  abundance.  The  sea-plants 
are  collected,  dried,  and  burned  in  large  pits,  the  ashes  of 
which  are  called  help.  Formerly  this  kelp  was  collected  on 
account  of  the  carbonated  alkali  which  it  contains  ;  its  value 
now  is  enhanced  on  account  of  the  iodides  and  chlorides 
which  are  found  in  it.  The  powdered  mass  is  dissolved  in 
cold  water,  which  is  afterward  evaporated  until  a  scum  forms 
on  the  surface.  The  solution  is  then  set  aside  to  cool,  when 
a  quantity  of  crystals  will  be  deposited.  By  a  further  evap- 
oration, more  crystals  may  be  obtained,  until  finally  the 
mother-liquor  ceases  to  yield  any  more.  The  dark-colored 
liquid  contains  the  iodides,  which  may  be  precipitated  by  a 
mixture  of  five  parts  of  sulphate  of  iron  and  two  parts  of  sul- 
phate of  copper.  The  precipitate  is  subiodide  of  copper, 
which,  by  treatment  with  sulphuric  acid,  the  deutoxide  of 


70 


PREPARATION  OF  THE  IODIDES. 


manganese  and  heat,  yields  iodine  in  violet  vapors,  which  by 
condensation  form  the  metallic-looking  crystals  of  iodine. 
There  are  other  methods  of  separating  the  iodides. 

Properties. 

Iodine  resembles  plumago  or  black  lead,  in  ontward  ap- 
pearance ;  it  is  a  crystalline  substance,  soft  and  brittle.  It 
melts  at  224°,  and  sublimes  at  347°.  Its  taste  is  very  acrid 
and  astringent ;  its  smell  is  somewhat  like  that  of  chlorine. 
Water  dissolves  about  one  part  in  seven  thousand  parts,  and 
receives  a  brown  color.  Alcohol  and  ether  dissolve  it 
abundantly;  and  so  do  iodide  of  potassium  and  hydriodic 
acid,  forming  brownish  red  solutions.  Iodine  in  solution,  as 
tincture,  or  in  iodide  of  potassium  preferably,  has  very  val- 
uable medicinal  properties.  It  is  regarded  as  a  specific  in 
the  reduction  of  glandular  swellings,  and  in  scrofulous  dis- 
eases. It  is  said  to  cause  the  pustules  of  small-pox  to  abort. 
In  photography,  it  is  impossible  to  estimate  its  value ;  for 
without  it,  the  art  could  not  exist  in  its  present  state. 

The  impurities  in  iodine  are  plumbago,  sulphide  of  anti- 
mony, and  iodide  of  cyanogen.  If  by  evaporation  on  a  piece 
of  porcelain  there  be  any  residue,  one  or  both  of  the  former 
impurities  may  be  present;  the  latter  impurity  is  of  rare 
occurrence. 

Tests :  Free  iodine  is  easily  recognized  by  the  formation 
of  a  deep  blue  color  when  mixed  with  a  solution  of  starch  ; 
and  this  blue  color  is  volatilized  by  heat.  The  iodine  in  an 
iodide  has  first  to  be  set  free  before  it  can  be  thus  tested. 
To  effect  this,  either  a  current  of  chlorine  is  passed  through 
the  solution,  or  nitric  acid  is  added  to  it ;  by  boiling  the  solu- 
tion afterward,  the  fumes  may  be  obtained  and  thus  tested. 

Preparation  of  Hydriodio  Acid. 

Hydriodic  Acid.  —  Symbol,  I  H.    Combining  Proportion,  128yL-.  Specific 

Gravity,  4.43. 

This  substance  is  a  condensable  gas  ;  at  a  temperature  of 
5 9°. 8,  it  solidifies  into  a  transparent,  colorless  mass ;  and 
water  absorbs  a  large  quantity.  The  strongest  liquid  hydri- 
odic acid  has  a  specific  gravity  of  lr7o,  when  it  boils  at  a 
temperature  between  257°  and  262°.  It  is  not  a  stable  com- 
pound ;  oxygen  from  the  air  is  absorbed,  and  iodine  is  lib- 
erated and  dissolved  by  it.  Chlorine  and  bromine  decom- 
pose it. 

Hydriodic  acid  may  be  obtained  by  several  methods. 


PREPARATION  OF  THE  IODIDES. 


From  the  property  which  iodine  possesses  of  abstracting 
hydrogen  from  several  of  its  compounds,  as  from  phosphide 
of  hydrogen,  hydrosulphuric  acid,  ammonia  and  organic 
compounds,  methods  have  been  devised  to  obtain  hydriodic 
acid  by  their  mixture.  Thus,  by  diffusing  iodine  in  powder 
through  water,  and  then  passing  a  current  of  hydrosulphuric 
acid  through  the  solution  as  long  as  iodine  is  thus  taken  up 
and  the  fluid  is  rendered  colorless.  By  this  process,  sulphur 
is  deposited  and  iodine  takes  its  place.  By  filtration,  the 
sulphur  is  removed ;  by  heat,  the  superfluous  hydrosulphuric 
acid  is  driven  away.  The  remaining  transparent  solution  is 
hydriodic  acid. 

A  solution  of  iodide  of  barium  may  be  decomposed  by  an 
equivalent  proportion  of  sulphuric  acid,  and  by  filtration  from 
the  insoluble  sulphate  of  baryta,  hydriodic  acid  is  obtained  in 
solution. 

Phosphorus  combines  very  vividly  with  iodine,  and  the 
iodide  of  phosphorus,  when  it  comes  in  contact  with  water,  is 
decomposed  into  hydriodic  acid  and  phosphoric  acid.  Liebig 
has  availed  himself  of  this  property  in  the  preparation  of  the 
iodide  of  lithium,  barium,  calcium,  potassium,  sodium,  etc. 

Lithium. — Symbol,  Li.     Combining  Proportion,  6T%. 

Barium. — Symbol,  Ba.    Combining  Proportion,  68y57.    Specific  Gravity,  4. 

Calcium. — Symbol,  Ca.   Combining  Proportion,  20. 

Potassium. — Symbol  K.  Combining  Proportion,  39. 

Sodium. — Symbol,  Na.    Combining  Proportion,  23.   Specific  Gravity,  0.97. 

Ammonium. — Symbol  NH4=Am.    Combining  Proportion,  18. 

Cadmium. — Symbol,  Cd.    Combining  Proportion,  56.    Specific  Gravity,  8.6. 

Take  one  part  of  phosphorus,  twenty-four  parts  of  iodine, 
and  forty  of  warm  water ;  mix  them  intimately  in  a  Wedg- 
wood mortar  by  means  of  the  pestle.  The  color  of  the  fluid 
is  at  first  dark  brown,  but  becomes  transparent  as  soon  as 
the  decompositions  are  effectuated.  The  heat  of  a  water- 
bath  and  friction  will  soon  complete  the  action.  By  this 
operation,  iodine  and  phosphorus  combine,  so  as  to  form 
iodide  of  phosphorus,  which  becomes  resolved  into  hydriodic 
acid  and  phosphoric  acid  by  the  decomposition  of  the  water. 
A  little  free  iodine  added  to  the  transparent  solution  prevents 
the  formation  of  phosphorous  acid. 

Iodide  of  Barium. 

To  the  transparent  solution  above  obtained,  by  decantation 
from  any  remaining  phosphorus,  add,  in  the  first  place,  carbo- 
nate of  baryta  as  long  as  effervescence  ensues,  and  afterward 


12 


PREPARATION  OF  THE  IODIDES. 


a  little  water  of  baryta,  so  that  the  mixture  becomes  slightly 
alkaline.  By  this  decomposition  phosphate  of  baryta  is 
formed  from  the  phosphoric  acid  and  the  carbonate  of 
baryta ;  and  from  the  hydriodic  acid,  and  the  carbonate  of 
baryta,  iodide  of  barium  is  the  resulting  formation  ;  and  car- 
bonic acid  is  liberated  as  gas.  The  iodide  of  barium,  being 
soluble,  is  separated  from  the  insoluble  phosphate  by  filtra- 
tion. A  current  of  carbonic  acid  is  now  passed  through 
the  filtrate,  in  order  to  combine  with  any  remaining  solution 
of  baryta,  and  the  mixture  is  again  filtered. 

Iodide  of  Calcium. 

This  salt  is  obtained  precisely  in  the  same  way  as  the  pre- 
ceding substituting  only  milk  of  lime  for  the  barytic  salt. 
Both  these  salts  crystallize,  when  slowly  evaporated ;  they 
are,  too,  both  deliquescent.  From  either  iodide  of  barium 
or  iodide  of  calcium  the  alkaline  iodides  are  easily  formed. 

Iodide  of  lithium. 

Add  two  ounces  of  carbonate  of  lithia  to  the  iodide  of 
either  barium  or  calcium  solutions  produced  from  seven 
ounces  of  iodine  by  the  preceding  manipulation.  The  car- 
bonate is  previously  levigated  in  water  to  an  impalpable 
consistency.  The  mixture  is  frequently  stirred  during  the 
twenty-four  hours  it  is  allowed  to  stand,  in  order  to  effect 
the  complete  precipitation  of  baryta  or  lime.  The  solution 
of  iodide  of  lithium  is  now  separated  by  filtration  from  the 
insoluble  carbonate  of  baryta  or  lime.  If  the  iodide  of  ba- 
rium or  of  lime  has  not  been  thoroughly  decomposed,  add  a 
cold  solution  of  carbonate  of  lithia  as  long  as  any  precipitate 
is  formed. 

Iodide  of  Potassium. 

Digest  a  hot  solution  of  sulphate  of  potassa  in  a  solution 
of  iodide  of  calcium  in  the  proportion  of  their  equivalents 
for  six  or  eight  hours.  Double  decomposition  ensues,  the 
sulphuric  acid  and  oxygen  of  the  potass,a  combine  with  the 
lime  to  form  sulphate  of  lime,  whilst  the  iodine  and  potas- 
sium enter  into  combination  to  form  iodide  of  potassium. 
By  filtration  through  cloth  these  two  salts  are  separated. 
The  liquid,  containing  probably  still  some  iodide  of  calcium 
and  solution  of  sulphate  of  lime,  is  evaporated  and  then 
treated  with  pure  carbonate  of  potassa  as  long  as  any  pre- 
cipitate is  produced.    The  insoluble  lime  is  again  separated, 


PREPARATION  OF  THE  IODIDES. 


IS 


and  the  filtrate  is  evaporated  to  crystallization.  The  mother 
liquor  is  afterward  evaporated  to  dryness. 

Iodide  of  Sodium  and  Iodide  of  Ammonium. 

These  two  salts  may  be  prepared  in  like  manner,  either 
from  the  iodide  of  barium  or  of  calcium,  by  the  substitution 
in  one  case  of  sulphate  and  carbonate  of  soda,  and  in  the 
other  of  sulphate  and  carbonate  of  ammonia.  The  results 
are  better  with  the  iodide  of  barium,  owing  to  the  more 
perfect  insolubility  of  the  sulphate  of  baryta  after  decompo- 
sition. Both  of  these  iodides,  as  well  as  that  of  potassium, 
may  be  obtained  by  the  direct  action  of  iodine  on  the  caustic 
alkalies.  In  this  way  iodine  is  added  to  a  solution  of  potassa, 
for  instance,  until  the  latter  becomes  slightly  colored ;  the 
solution  so  obtained  contains  iodide  of  potassium  and  iodate 
of  potash ;  it  is  evaporated  to  dryness,  and  then  heated  to 
redness,  in  order  to  convert  the  iodate  of  potash  into  iodide 
of  potassium  by  driving  off  its  oxygen.  The  fused  mass  is 
afterward  dissolved  and  crystallized.  Sulphuretted  hydro- 
gen is  sometimes  used  to  decompose  the  iodate. 

Another  method,  similar  to  the  first,  consists  in  first  ob- 
taining either  the  iodide  of  iron  or  of  zinc,  by  mixing  iodine, 
water,  and  iron-filings,  or  iodine,  water,  and  zinc-filings,  to- 
gether, and  then  heating  the  mixture  until  the  combination 
is  complete,  which  is  indicated  by  its  becoming  colorless. 
The  filtered  solution  is  next  decomposed  completely  by  add- 
ing solution  of  carbonate  of  potassa  as  long  as  any  precipi- 
tate takes  place.  The  precipitate,  which  is  either  carbonate 
of  iron  or  of  zinc,  is  removed  by  filtration  ;  and  the  filtrate 
is  evaporated  to  crystallization. 

Iodide  of  Cadmium. 

This  very  important  iodide  is  formed  precisely  in  the 
same  way  as  iodide  of  iron  or  of  zinc,  by  gently  heating  a 
mixture  of  the  filings  of  cadmium,  water,  and  iodine,  until 
the  solution  becomes  colorless. 

Impurities  of  the  Iodides. 

The  iodides  which  are  formed  by  the  direct  contact  of  the 
two  elements  are  quite  pure  if  the  materials  are  pure  ;  where- 
as, if  the  iodides  arise  from  double  decomposition,  the  com- 
bination may  sometimes  fail  in  accuracy,  in  which  case  car- 
bonates and  sulphates  of  foreign  ingredients  and  iodates  of 
the  same  base  may  be  found  in  such  iodides  ;  chlorides  may 


74 


PREPARATION  OF  THE  IODIDES. 


De  present,  too,  in  the  decomposing  carbonates  and  sulphates, 
so  that  we  may  sometimes  expect  to  find  them  with  the  otfher 
impurities. 

Tests  of  the  Purity  of  the  Iodides. 
No  precipitate  is  produced  in  a  pure  iodide  by  solution  of 
mloride  of  barium.  If  a  precipitate  results  from  the  introduc- 
tion of  this  test,  one  or  all  of  the  following  acids  are  probably 
indicated :  carbonic,  iodic,  and  sulphuric.  Other  acids  might 
be  indicated,  but  not  probably,  because  materials  are  not  used 
in  the  preparation  of  the  iodides  containing  the  acids  hinted 
at,  as,  for  instance,  oxalic,  sulphurous,  silicic,  chromic,  hydro- 
fluoric, phosphoric,  and  boracic.  Supposing,  however,  a  pre- 
cipitate is  formed  when  the  test  is  added,  then  a  carbonate, 
iodate,  or  sulphate  may  be  one  or  all  present.  The  next  test 
is  to  find  out  which  or  how  many  of  the  three  are  present. 
Add,  therefore,  nitric  acid  to  the  precipitate  ;  if  it  becomes 
dissolved,  there  is  no  sulphate  in  the  iodide.  Carbonic  acid 
or  an  alkaline  carbonate  added  to  lime-water  produces  a 
milkiness  caused  by  the  formation  of  the  insoluble  carbonate 
kof  lime  ;  and  an  iodate  in  solution  is  recognized  by  the  addi- 
tion of  chlorine-water,  or  citric,  or  tartaric  acid,  which  liber- 
ates free  iodine,  afterward  made  manifest  by  solution  of 
starch.  The  chlorides  are  tested  for  as  follows  :  in  a  given 
quantity  of  the  iodide  precipitate  with  solution  of  nitrate  of 
silver,  until  nothing  more  falls  as  sediment ;  dissolve  this 
sediment  in  ammonia,  and  then  add  nitric  acid  ;  if  a  chloride 
is  present,  a  white  flocculent  precipitate  will  be  produced, 
which  is  chloride  of  silver. 


CHAPTEE  XI. 


BROMINE. 

Bromines — Symba,  Br.  Combining  Proportion,  80.  Specific  Gravity,  2.966, 

This  peculiar  substance  was  discovered  in  1826  by  Balard, 
of  Montpellier.  It  was  originally  obtained  from  the  uncrys- 
tallizable  mother-liquor  of  sea-water,  called  bittern.  It  oc- 
curs in  sea-water  in  small  quantity  as  bromide  of  magnesium, 
or  of  an  alkali ;  but  in  much  larger  quantities  in  several 
mineral  springs,  as,  for  instance,  at  Kreuznach,  Cheltenham, 
etc.,  and  is  naturally  found  in  many  marine  plants  and  ani- 
mals. 

Preparation  of  Bromine. 

The  solution  of  the  bromides  obtained  by  evaporation  of 
sea- water,  spring-water,  or  from  the  ashes  of  certain  plants 
and  animals,  is  submitted  to  a  current  of  chlorine,  which 
takes  the  place  of  the  bromine  in  the  salts.  When  the 
liquid  ceases  to  assume  a  deeper  color  from  the  introduction 
of  chlorine,  (and  great  care  must  be  taken  not  to  add  too 
much,  because  it  combines  with  the  bromine  as  soon  as  there 
is  no  base  present  for  it  to  combine  with,)  it  is  well  shaken 
with  ether,  which,  taking  up  the  bromine,  ascends  and  swims 
on  the  surface.  This  film  is  then  decanted,  or  otherwise 
separated,  and  mixed  with  a  strong  solution  of  potassa,  by 
which  both  bromate  and  bromide  of  potassium  are  formed  ; 
the  ether  may  now  be  removed  by  distillation,  and  the  re- 
maining solution  is  evaporated  to  dryness.  The  residual 
mass  is  then  fused,  whereby  the  bromate  of  potassa  is  con- 
verted into  bromide  of  potassium,  analogously  with  the 
iodate  or  chlorate  under  similar  circumstances.  By  distill- 
ing the  resulting  bromide  with  sulphuric  acid  and  peroxide 
of  manganese,  bromine  passes  off  as  vapor,  and  a  sulphate  of 
the  base  remains  in  the  retort  together  with  the  manganese 
in  a  lower  state  of  oxydation. 

Bromine  thus  obtained  contains  water  and  bromide  of  car- 


76 


BROMINE. 


bon.  The  water  is  removed  by  a  second  distillation  over 
recently  fused  chloride  of  calcium.  Bromine  is  a  brownish- 
red  liquid,  which  solidifies  at — Y0T2o>  volatilizes  very  rapidly 
when  exposed  to  the  air,  and  boils  at  about  145°.  Its  smell 
is  very  disagreeable  and  pungent.  A  drop  on  the  cuticle 
destroys  it  and  produces  a  sore.  It  is  soluble  in  33T3¥  parts 
of  water,  and  this  solution  is  decomposed  by  exposure  to 
light  into  hydrobromic  acid. 

Test :  Chlorine  liberates  bromine  from  all  its  soluble  com- 
pounds. Ether  combines  with  it  and  collects  it ;  solution  of 
starch  produces  a  yellowish-red  color  with  it ;  it  distills  as  a 
liquid. 

Hydrobromic  Acid. 
Symbol,  Br  H.  Combining  Proportion,  81.  Spec.  Gra v.,  2.73. 
This  acid  is  very  analogous  in  its  formation  and  reactions 
to  hydriodic  acid.  It  can  be  prepared  by  mixing  directly 
phosphorus,  water,  and  bromine,  or  from  a  mixture  of  six 
parts  of  crystallized  sulphite  of  soda,  three  parts  of  bromine, 
and  one  of  water,  and  by  distillation.  It  can  be  obtained 
also  by  transmitting  a  current  of  hydrosulphuric  acid  through 
water,  holding  in  solution  or  suspension  a  small  quantity  of 
bromine  ;  sulphur  is  deposited ;  the  hydrogen  combines  with 
the  bromine.  By  a  gentle  heat  the  fumes  of  hydrosulphuric 
acid  are  expelled  ;  and  by  filtration  the  hydrobromic  acid  is 
obtained  in  solution. 

Bromides. 

These  binary  combinations  can  be  obtained,  as  a  general 
thing,  by  manipulating  precisely  as  in  the  preparation  of  the 
iodides,  with  the  single  substitution  of  bromine  for  iodine. 
They  contain  in  like  manner,  and  for  the  same  reason,  the 
same  impurities  which  may  be  manifested  by  the  same  tests, 
with  the  exception  of  bromic  acid  instead  of  iodic;  the 
former  of  which  is  decomposed  by  chlorine. 

Preparation  of  the  Chlorides. 

Chlorine. — Symbol,  CI.    Combining  Proportion,  35.5.    Spec.  Grav.,  2.47. 

This  substance  was  discovered  in  1774  by  Scheele.  Its 
affinity  for  other  elements  is  very  great,  so  that  it  does  not 
exist  free  or  uncombined.  The  great  geological  formation 
of  rock-salt  is  a  chloride  of  sodium,  to  which  the  ocean  owes 
its  saline  taste.  It  combines  with  most  of  the  metalloids  as 
well  as  the  metals,  giving  rise  to  some  of  the  most  import- 
ant and  interesting  combinations  in  chemistry.  Chlorine, 
iodine,  bromine,  and  fluorine  form  analogous  binaries  with 


BROMINE. 


71 


hydrogen  and  the  metals ;  but  chlorine  has  greater  affinities 
for  bases  than  any  of  the  others ;  it  is,  therefore,  employed 
in  separating  iodine  and  bromine  from  their  combinations. 

Preparation. 

Chlorine  may  be  obtained  from  any  of  its  binary  combina- 
tions by  double  decomposition.  Thus  hydrochloric  acid  is  a 
binary  consisting  of  chlorine  and  hydrogen ;  now  by  adding 
to  hydrochloric  acid  a  material  in  which  oxygen  is  loosely 
combined,  hydrogen  and  oxygen  unite  to  form  water,  chlo- 
rine is  liberated,  and  a  chloride  of  the  base  is  at  the  same 
time  formed.  Take,  for  instance,  four  parts  of  hydrochloric 
acid,  one  part  of  the  binoxide  or  black  oxide  of  manganese, 
and  the  same  quantity  of  water.  Mix  these  ingredients  in  a 
flask  or  retort  connecting  with  a  jar  filled  with  warm  water 
and  inverted  over  the  pneumatic  trough,  or  by  a  tube  dip- 
ping to  the  bottom  of  a  large  tumbler.  By  applying  heat, 
either  from  a  lamp  or  sand-bath,  an  effervescence  is  pro- 
duced, being  the  result  of  the  decomposition  just  alluded  to. 
The  gas  as  it  passes  out  displaces  the  water  in  one  case  and 
the  air  in  the  latter. 

The  mode  by  which  it  is  procured  from  a  chloride  consists 
in  first  obtaining  from  the  chloride  hydrochloric  acid,  and 
then  proceeding  as  before.  But  the  two  operations  are  com- 
bined in  one,  that  is,  they  take  place  consentaneously  by 
mixing  all  the  materials  together  which  are  required  in  their 
separate  formations  as  follows  :  take  three  parts  of  common 
salt,  five  of  sulphuric  acid,  five  of  water,  and  four  of  binox- 
ide of  manganese,  and  apply  heat  as  before ;  the  same  re- 
sult will  ensue  as  in  the  first  case. 

Properties. 

This  substance  is  a  heavy  gas  of  a  greenish-yellow  color, 
and  exceedingly  suffocating  odor.  Under  a  pressure  of  four 
atmospheres  this  gas  is  condensed  into  a  liquid  of  a  bright 
yellow  color,  whose  specific  gravity  is  1.33.  It  is  soluble  in 
water,  which  takes  up  and  dissolves  about  two  volumes  of 
this  gas,  and  receives  the  taste,  odor,  and  other  properties 
of  the  gas.  With  very  cold  water  chlorine  enters  more 
abundantly  into  combination,  forming  a  crystalline  hydrate. 
Chlorine  in  solution,  when  exposed  to  the  light,  soon  de- 
composes the  water,  giving  rise  to  hydrochloric  acid.  Chlo- 
rine has  an  exceedingly  great  affinity  for  hydrogen,  and  re- 
moves this  latter  body  from  many  of  its  combinations,  as, 
for  example,  from  ammonia ;  still  dry  chlorine  and  hydro- 


18 


BKOMINE. 


.  gen,  when  mixed  and  kept  in  the  dark,  do  not  combine  ;  if 
brought  into  the  full  blaze  of  the  sun,  they  combine  and  ex- 
plode ;  if  exposed  to  diffused  light,  they  combine  silently  into 
hydrochloric  acid.  Its  action  upon  metals  in  a  state  of  fine 
division  is  in  many  cases  very  energetic ;  if  a  piece  of  bronze 
or  gold-leaf  be  injected  into  a  tumblerful  of  the  moist  gas, 
the  combination  is  so  energetic  as  to  produce  flame.  The 
moist  gas  combines  with  the  hydrogen  of  organic  colors  and 
bleaches  them ;  these  colors  can  not  be  restored,  because  the 
hydrogen  can  not  be  restored  organically ;  hence  we  say  in 
such  an  instance  that  the  color  has  been  destroyed.  In  like 
manner  moist  chlorine  removes  the  hydrogen  from  putrid 
and  miasmatic  substances,  as  from  fish,  meat,  and  offensive 
localities.  It  is,  therefore,  denominated  a  disinfecting  agent. 
Its  combination  with  the  hydrate  of  lime  is  the  form  in  which 
it  is  used  both  for  bleaching  and  disinfecting. 

Chloride  of  Lime,  Ghlorinetted  Lime,  etc. 

This  substance  is  prepared  by  passing  chlorine  through 
sets  of  chambers  or  compartments  of  wicker-work  containing 
layers  of  hydrate  of  lime.  The  lime  absorbs  a  large  quantity 
of  the  gas,  and  probably  combines  with  it  in  the  formation 
of  a  hypochlorite  of  lime.  Chloride  of  lime  is  soluble  to 
some  extent  in  water,  giving  to  it  an  alkaline  reaction  ;  its 
bleaching  powers  are  more  effectual  when  an  acid  is  added, 
which  liberates  the  chlorine.  This  substance  is  now  used  in 
photography  in  the  preparation  of  the  gold-toning  bath. 
When  added  to  chloride  of  gold,  which  is  slightly  acid,  it 
renders  it  alkaline,  and  at  the  same  time  chlorine  is  liberated, 
which  assists  in  producing  pure  whites  on  the  paper,  and  in 
furnishing  a  chloride  of  gold  which  is  more  effectual  in  ton- 
ing. 


CHAPTER  XII. 


NORMAL  OR  PLAIN"  COLLODION",  IODIZED  COLLODION,  BROMO* 
IODIZED  COLODION". 

Normal  or  plain  collodion  is  a  solution  of  pyroxyline  in  a 
mixture  of  ether  and  alcohol,  ready  for  being  iodized  or  bro- 
mo-iodized.  This  sort  of  collodion  when  preserved  in  well 
corked  bottles  becomes  clearer  with  age,  and  the  sediment 
occupies  continually  less  space.  After  it  has  stood  for  a  week 
or  two,  the  clear  supernatant  solution  is  decanted  by  means 
of  a  syphon,  syringe,  or  stop-cock  from  the  residue  of  undis- 
solved pyroxyline  beneath,  and  again  put  aside  to  settle. 
There  is  no  fixed  rule,  arising  from  chemical  equivalents  or 
combining  proportions,  by  which  to  institute  a  fixed  formula 
for  the  preparation  of  normal  or  plain  collodion.  I  have  se- 
lected those  which  may  be  relied  upon. 

Take  of  ether,  specific  gravity,  .715  1000  part3  by  weight. 
"    "  Alcohol,  (absolute,)  .    .    .   1000  "      "  " 

In  another  vessel  shake  together  thoroughly — 

Alcohol,  (absolute,)    .    .    .  850  parts. 
Pyroxyline,  45  " 

As  soon  as  the  pyroxyline  is  completely  covered  and  satu- 
rated with  the  alcohol,  add  the  mixture  of  alcohol  and  ether, 
and  shake  well  until  the  cotton  has  completely  disappeared. 
Cork  the  vessel  carefully,  which  is  supposed  to  be  full,  and 
put  it  aside  in  a  cool,  dark  place  for  a  week  or  two,  as  before 
directed. 

If  a  glutinous  collodion,  or  a  collodion  with  more  body  be 
desired,  such  as  is  required  in  the  transfer  of  the  collodion 
film  upon  glazed  leather,  etc.,  as  much  as  fifty  parts  of  py- 
roxyline may  be  dissolved  in  the  above  proportions  of  alco- 
hol and  ether ;  on  the  contrary,  if  a  thin  collodion  be  required 
for  the  flowing  of  large  plates,  the  proportion  may  be  as  low 
as  thirty-six  or  forty  parts  of  the  prepared  cotton.  Normal 
collodion  for  present  use  may  be  filtered  ;  but  it  is  far  from 
being  as  pure  by  filtration  as  by  subsidence.    Filte  rs  for  such 


80 


NORMAL  OR  PLAIN  COLLODION. 


purposes  may  be  procured  of  the  photographic  establish, 
ments,  by  which  the  filtration  proceeds  without  the  contents 
coming  in  contact  with  the  atmosphere.  The  above  propor- 
tions are  for  the  preparation  of  what  is  denominated  alcohol 
collodion,  which  produces  a  soft,  short,  and  structureless  film 
on  the  glass  plate. 

Bromo-idiozing  Solutions  for  the  same. 


Take  of  Alcohol,  (absolute,)  100  parts. 

"    Iodide  of  sodium,  8  " 

u    Iodide  of  cadmium,  8  " 

"    Bromide  of  cadmium,  4  " 

Or, 

Take  of  Alcohol,  (absolute,)  100  parts. 

"    Iodide  of  lithium,  10  " 

"    Bromide  of  lithium,  5  " 

Or, 

Take  of  Alcohol,  (absolute,)  100  parts. 

"    Iodide  of  lithium,  6  " 

"    Iodide  of  cadmium,  6  " 

"    Bromide  of  cadmium,  2  " 

Or, 

Take  of  Alcohol,  (absolute,)  100  parts. 

"  Iodide  of  cadmium,  ....  10  " 
"    Bromide  of  ammonium,      ...      5  " 


Dissolve  the  salts  in  each  case  in  the  given  quantity  of  al- 
cohol, shaking  the  mixture  frequently,  and  preserve  it  in 
well-closed  bottles  and  in  a  dark  place. 

Collodion  for  photographic  purposes  is  prepared  from  a 
mixture  of  plain  collodion,  and  one  of  the  bromo-iodizers 
above  given,  in  the  proportion  of  ten  parts  of  the  former  to 
one  of  the  latter.  The  mixture  requires  to  be  placed  aside 
for  a  day  or  two,  before  it  arrives  at  its  maximum  sensitive- 
ness. 

Many  operators  prepare  their  collodion  directly  with  the 
requisite  quantity  of  iodizing  and  bromo-iodizing  materials, 
of  which  the  following  selection  contains  some  of  the  best 
formula?. 

Formula  of  Lieut,-  Colonel  Stuart  Worthy. 

Ether,'   1  ounce. 

Alcohol,  .802, .......  2i  " 

Iodide  of  lithium,   15  grains. 

Bromide  of  lithium,      ....  6£  " 

The  pyroxyline  is  first  steeped  in  the  bromo-iodiozed  alco- 
hol, and  the  ether  then  added.    These  proportions  produce 


NORMAL  OR  PLAIN  COLLODION. 


81 


a  very  fluid  collodion,  which  is  quite  an  advantage  in  coat* 
ing  large  plates,  where  a  very  even  film  is  required.  It  is 
said  to  be  well  adapted  for  instantaneous  pictures.  The  sen- 
sitizing bath,  which  is  used  with  this  collodion,  will  be  found 
amongst  the  list  of  silver  baths  given  hereafter. 

OmmegancUs  Formulas  for  Portraits  and  Landscapes. 


For  Portraits  of  short  exposure. 

Ether,   667  parts. 

Alcohol,   333  " 

Iodide  of  ammonium,     ....  6  " 

Iodide  of  cadmium,      ....  6  '* 

Bromide  of  cadmium,    ....  3  " 

Pyroxyline,   12  " 


This  collodion  is  sure  to  be  thick  enough ;  if  too  thick, 
however,  it  can  be  rendered  more  fluid  by  the  addition  of  an 
appropriate  quantity  either  of  ether  or  absolute  alcohol.  If 
more  than  one  tenth  of  the  original  volume  be  added,  it  will 
be  necessary  to  mix  with  this  the  corresponding  quantity  of 
the  bromo-iodizers. 

For  Landscapes,  Views,  and  Direct  Transparent  Positives. 


Ether,   667  parts. 

Alcohol,   333  " 

Iodide  of  zinc,   6  " 

Iodide  of  cadmium,  ....  6  " 
Bromide  of  cadmium,  ....  3  " 
Proxy  line,  12  " 


In  this,  as  also  in  the  preceding  formula,  weigh  out  the  salts 
first ;  put  them  into  a  bottle  of  the  proper  capacity ;  add  the 
alcohol,  and  dissolve  them  by  frequent  shaking  ;  next  add  the 
ether  and  mix ;  finally  introduce  the  pyroxyline  in  small  flocks 
at  a  time,  and  shake  until  the  cotton  is  dissolved.  After  the 
solution  is  eflected  the  collodion  is  put  aside  in  a  cool,  dark 
chamber,  and  allowed  to  settle  for  a  couple  of  weeks.  The 
first  collodion  will  keep  for  a  long  time ;  the  latter  is  less 
stable,  but  more  sensitive  to  certain  colors  of  foliage. 

Formulas  of  Disderi. 

NO.  I. — COLLODION  FOR  WINTER. 


First  Formula. 
Alcohol — spec.  grav.    .813,  .    4000  grains. 

Ether,         "      "      .720,     .  6000  " 

Pyroxyline,  110  " 

Iodide  of  ammonium,  ....      60  " 

Iodide  of  cadmium,     ....    40  " 

Bromide  of  ammonium,  ...       6  " 

Bromide  of  cadmium,  ....     4  " 

Iodine,   5  " 


82 


NORMAL  OR  PLAIN  COLLODION. 


Second  Formula, 

Alcohol — spec.  grav.    .813,  .     4000  grains. 

Ether,         "     "       .720,     .  6000  " 

Pyroxyline,  110  " 

Iodide  of  ammonium,     ...      50  " 

Iodide  of  potassium,     ....    50  " 

Bromide  of  ammonium,  ...      10  " 

Bromide  of  potassium,  ....    10  " 

Iodine,   5  " 

The  iodide  and  bromide  of  potassium  are  dissolved  in  the 
smallest  quantity  of  water.  A  quarter  of  the  prescribed  quan- 
tity of  alcohol  is  poured  into  a  clean  bottle ;  the  pyroxyline 
is  then  introduced,  and  the  mixture  is  well  shaken.  After 
this  operation  the  ether  is  added.  The  salts  of  iodine  and 
bromine  are  next  weighed  and  dissolved  in  the  remaining 
quantity  of  alcohol,  and  then  mixed  with  the  solution  con- 
taining the  cotton.  The  collodion  is  put  aside  for  a  day  oi 
two,  and  then  either  decanted  or  filtered. 


COLLODION  FOR  SPRING. 

Alcohol,  (as  before,)     .    .    .    5000  parts. 

Ether,  .         "   5000  " 

Pyroxyline,  100  " 

Iodide  of  ammonium, .    ...      50  " 

Iodide  of  cadmium,     ....    50  u 

Bromide  of  ammonium,  ...      10  " 

Bromide  of  cadmium,  .    .    .    .    10  " 

Iodine,   5  " 

Second  Formula. 

Alcohol  and  ether,  of  each,   5000  grains. 

Pyroxyline,   100  " 

Iodine  of  ammonium  and  of  potassium,  of  each,  ...  50  " 
Bromide  of  ammonium,  and  bromide  of  potassium,  of  each,  5  " 
Iodine,   5  " 


COLLODION  FOR  SUMMER. 

Alcohol,  (as  before,)     .    .    .    4000  grains. 

Ether,  "    6000  " 

Pyroxyline,  80  " 

Iodide  of  ammonium,  ....     50  " 

Iodide  of  cadmium,     ....    30  " 

Bromide  of  ammonium,  ...       5  " 

Bromide  of  cadmium,  2  " 

Iodine,   2  " 

For  copying  engravings,  etc.,  all  that  is  required  is  a  very 
simply  iodized  collodion,  without  any  bromide. 


NORMAL  OR  PLAIN  COLLODION. 


83 


Formula  for  Copying  Collodion. 


Alcohol,  (absolute,)      .    .    .    5000  grains. 


Ether,  .720,   5000 

Iodide  of  cadmium,  ....  100 
Pyroxyline,  from  .  .  .  75  to  100 
Iodine,  2 


The  collodion  film,  whether  iodized  or  bromo-iodized,  is  ren- 
dered sensitive  by  immersion  in  a  bath  of  nitrate  of  silver, 
which  will  be  described  in  the  following  pages. 

(Owing  to  the  instability  of  collodion  when  once  iodized, 
it  has  been  proposed  to  invert  the  operations,  and  to  mix  with 
the  collodion  an  equivalent  quantity  of  the  nitrate  of  silver, 
instead  of  the  iodizers  or  bromo-iodizers,  and  then  to  sensi- 
tize the  film  in  a  bath  as  follows : 


As  soon  as  withdrawn  from  this  bath,  the  collodion  plate 
is  washed  in  distilled  water,  and  either  used  immediately  by 
immersing  it  in  a  weak  solution  of  nitrate  of  silver,  or  put 
away  to  dry.  This  process  is  due  to  Ch.  D'Orma,  and  re- 
mains to  be  tried.)  Whatever  may  be  the  difference  of  the 
composition  of  the  collodion,  arising  from  the  variety  of  for- 
mulas that  exist — for  there  is  scarcely  a  single  operator  that 
does  not  boast  of  his  own  formula — each  collodionized  plate, 
when  the  film  has  sufficiently  dried,  is  submitted  to  the  chem- 
ical influence  of  a  solution  of  nitrate  of  silver,  in  order  to  ob- 
tain by  double  decomposition  in  and  on  the  film  an  iodide, 
or  a  bromo-iodide  of  silver,  which  is  sensitive  to  the  actinic 
influence  of  light.  If  the  film  contained  a  pure  iodide,  or  a 
pure  bromo-iodide  of  silver,  without  the  presence  of  a  nitrate, 
the  results  would  not  be  satisfactory.  The  nitrates,  or  nitro- 
genized  organic  substances  seem  to  be  essential  as  accesso- 
ries in  the  photographic  operation  of  producing  collodion  posi- 
tives and  negatives.  The  most  important  salt  in  photogra- 
phic chemistry  is  nitrate  of  silver ;  it  is  the  salt  from  which 
most  of  the  other  silver  salts  are  obtained,  and  is  besides  a 
very  costly  article,  and  deserves  therefore  to  be  treated  with 
all  due  respect.  Hence  the  following  chapter  is  devoted  to 
its  service  chiefly. 


Distilled  water, 
Alcohol,      .    .    .  . 
Iodide  of  ammonium, 
Iodide  of  cadmium,  . 
Iodide  of  zinc,    .  . 
Bromide  of  zinc, 


100  parts. 


25  " 

2  " 

4  " 

2  " 

2  " 


CHAPTBE  XIII. 


SILVER  SALTS    OF  SILVER. 

Silver.*— Symbol,  Ag.    Combining  Proportion,  108.    Spec,  gra v.,  10.474. 
Oxide  of  Silver. — Symbol,  Ag  0.    Combining  Proportion,  116. 
Chloride  of  Silver. — Symbol,  Ag.  CI.    Combining  Proportion,  143.5. 
Iodide  of  Silver. — Symbol,  Ag.  I.    Combining  Proportion,  234.36. 
Bromide  of  Silver. — Symbol,  Ag.  Br.    Combining  Proportion,  188. 
Sulphide  of  Silver. — Symbol,  Ag.  S.    Combining  Proportion,  124. 
Cyanide  of  Silver. — Symbol,  Ag.  Cy.    Combining  Proportion,  134. 
Nitrate  of  Silver. — Symbol,  Ag  0.  N05.    Combining  Proportion,  170. 
Hyposulphite  of  Silver. — Symbol,  AgO.  S2O2.    Combining  Proportion,  164. 
Sulphate  of  Silver. — Symbol,  AgO.  S03.    Combining  Proportion,  156. 
Nitrite  of  Silver. — Symbol,  AgO.  N03.    Combining  Proportion,  154. 

Silver. 

,  Silver,  like  gold,  is  found  in  a  native  state ;  frequently 

too  it  occurs  as  an  alloy  containing  gold,  which  is  recog- 
nized, when  the  silver  is  dissolved  in  nitric  acid,  as  the  black 
sediment  or  oxide  of  gold.  Arsenic  and  antimony  are  found 
also  alloyed  with  it.  Several  of  the  ores  of  lead  and  copper 
contain  silver. 

As  an  ore,  the  sulphide  is  the  most  abundant ;  horn  silver, 
or  the  chloride,  occurs  native,  as  also  the  carbonate  in  small 
quantity. 

Native  silver,  and  the  silver  in  the  native  sulphide,  are 
separated  in  one  case  from  the  investing  rocky  materials, 
and  in  the  other  from  sulphur  by  a  process  called  that  of 
amalgamation.  The  ores  and  the  rocky  mass  are  reduced 
to  powder,  and  then  roasted  in  a  reverberatory  furnace  with 
about  ten  per  cent  of  chloride  of  sodium,  which  converts  the 
silver  into  chloride  of  silver.  The  pulverized  mass  is  next 
put  into  barrels,  hung  horizontally  and  capable  of  being 
rotated  by  machinery.  It  is  mixed  with  a  certain  quantity 
of  water,  iron  and  quicksilver.  By  being  kept  in  continual 
agitation  for  eighteen  or  twenty  hours,  the  chloride  of  silver 
becomes  decomposed  by  the  iron,  whereby  chloride  of  iron 
is  formed,  and  the  silver  set  free.  Coming  in  contact  with 
the  mercury,  an  amalgam  is  formed,  which  flows  off  out  of 


SILVER  SALTS  OF  SILVER. 


85 


the  barrel  when  the  contents  are  made  fluid  by  the  addition 
of  water,  and  by  rotating  the  barrels  very  slowly.  The 
amalgam  is  then  subjected  to  pressure  through  chamois 
leather,  which  allows  the  mercury  to  permeate  through  its 
pores,  but  retains  the  amalgam.  By  distillation,  the  mercury 
can  be  expelled  from  the  silver  residue.  Copper  and  lead 
ores,  containing  silver,  are  treated  in  the  same  way. 

In  certain  ores  of  copper  and  lead,  silver  exists  in  small 
quantities,  and  is  melted  or  separated  by  amalgamation 
along  with  them.  If  the  quantity  is  sufficiently  great,  the 
silver  is  separated  by  a  process  called  cupellation,  which  is 
practised  in  the  mint  in  the  assay  of  metals  containing  sil- 
ver. A  cupel  is  formed  out  of  well-burnt  and  well-washed 
bone  ashes,  kneaded  into  a  thick  paste  with  water,  and 
forcibly  pressed  in  an  iron  ring.  Cupels  vary  in  size  from 
one  to  two  inches  in  diameter  or  more,  and  from  a  quarter 
of  an  inch  to  three  fourths  of  an  inch  thick,  hollowed  on  one 
side  in  the  concave  form  of  a  watch-glass.  They  are  after- 
ward dried  by  a  gentle  heat,  as  on  a  stove,  when  they  are 
ready  for  use.  The  metal,  consisting  of  copper,  silver  and 
a  large  excess  of  lead,  to  be  assayed,  or  the  silver  to  be 
purified,  is  placed  in  the  concavity  of  the  cupel,  which  rests 
on  a  muffle  in  a  furnace,  over  which  a  current  of  air  can 
flow  with  some  force.  It  soon  melts,  and  by  the  access  of 
the  draft  of  air,  the  surface  becomes  covered  with  a  film  of 
oxide ;  this,  as  it  forms,  is  removed.  Lead  oxidizes  first, 
and  finally  .the  copper  is  induced  to  oxidize  by  means  of  the 
oxide  of  lead,  and  forms  with  it  a  fusible  compound,  which 
sinks  into  the  pores  of  the  cupel.  As  soon  as  the  foreign 
metals  are  nearly  removed,  the  silver  assay  assumes  a  rounder 
shape,  and  when  the  last  trace  of  oxide  disappears,  there 
is  a  beautiful  play  of  prismatic  colors,  and  finally  the  silver 
button  becomes  very  brilliant,  and  exhibit  s  a  bright  flash  of 
light,  indicative  of  the  completion  of  the  operation. 

A  second  process  of  purifying  silver,  and  one  which  will 
be  found  better  adapted  to  the  wants  of  the  photographer, 
consists  in  dissolving  the  silver  of  commerce,  or  of  the  coin- 
age of  the  country,  in  pure  nitric  acid.  Take  one  ounce 
and  a  half  of  silver,  in  thin  laminaB,  or  in  filings,  one  fluid 
ounce  of  nitric  acid,  and  two  ounces  of  pure  rain  or  distilled 
water.  Mix  the  acid  and  the  water  in  a  glazed  porcelain 
dish,  or  in  a  glass  dish  ;  then  add  the  silver,  and  place  the 
vessel  with  its  contents  in  a  sand-bath,  and  apply  a  gentle 
heat.  The  silver  will  soon  disappear  in  the  solution.  By 
this  operation,  the  nitric  acid  is  easily  broken  up  into  its  com- 


86 


SILVER  SALTS  OF  SILVER. 


binations ;  one  portion  oxidizes  the  silver  and  liberates  per- 
oxide of  nitrogen  ;  whilst  a  second  combines  with  the  oxide 
so  formed,  and  produces  the  nitrate  of  the  oxide  of  silver. 
If  the  metal  was  impure,  as  is  most  likely,  and  it  contained 
copper,  the  solution  will  be  tinged  blue  according  to  the 
quantity  of  impurity.  A  small  drop  at  the  end  of  a  glass 
stirring-rod,  will  give  rise  to  a  brilliant  blue  color,  in  a 
wine-glass  full  of  water,  made  alkaline  with  ammonia,  if 
there  be  any  copper  present ;  or  a  steel  knitting-needle, 
dipped  in  the  solution,  becomes  coated  with  a  film  of  copper, 
on  the  same  conditions. 

Supposing  the  solution,  therefore,  contains  copper,  we  may 
proceed  as  follows  to  separate  it  from  the  silver.  Add 
to  the  solution  of  the  nitrate,  a  small  quantity  of  common 
salt  dissolved  in  water,  drop  by  drop,  as  long  as  a  floccu- 
lent  precipitate  is  formed.  When  flakes  of  the  chloride  of 
silver,  thus  produced  by  double  decomposition  by  means  of 
the  chloride  of  sodium,  no  longer  appear  on  the  addition 
of  the  salt  solution,  the  precipitate  is  allowed  to  subside  in 
a  dark  room,  or  it  is  poured  directly  on  a  filter,  and  the 
fluid  containing  copper,  etc.,  is  thrown  away.  The  precipi- 
tate is  now  well  washed  by  repeatedly  filtering  pure  hot 
water  over  it,  until  a  drop  no  longer  produces  a  blue  tinge 
with  ammonia.  The  chloride  is  now  dried.  Next  weigh 
the  chloride,  and  take  twice  its  weight  of  carbonate  of 
potassa,  and  fuse  the  latter  in  a  crucible ;  when  fused,  add 
gradually  to  it  the  dry  chloride  of  silver,  which  will  be  de- 
composed, as  well  as  the  carbonate  of  potassa.  The  chlori'de 
leaves  the  silver  and  gives  rise  to  chloride  of  potassium, 
whilst  the  carbonic  acid  and  oxygen  escape,  and  the  silver 
remains  diffused  through  the  mass.  By  raising  the  tem- 
perature, the  silver  sinks  into  a  button  at  the  bottom,  and 
the  fused  chloride  of  potassium  swims  on  the  surface.  The 
melted  mass  may  now  be  poured  out  into  a  pail  of  water,  or 
upon  a  hollow  stone.  The  silver  thus  obtained  and  washed, 
will  be  quite  free  from  copper,  and  all  other  metals,  except- 
ing lead  or  mercury,  which  might  be  present.  If  lead  were 
present  in  the  nitrate,  the  addition  of  sulphuric  acid  would 
produce  a  precipitate ;  and  the  presence  of  mercury  is  easily 
shown  by  introducing  a  piece  of  polished  copper  wire  into 
a  small  quantity  of  the  nitrate  in  solution,  by  which  it  will 
be  covered  with  a  film  of  mercury  when  the  latter  is  pres- 
ent. 

Chloride  of  silver  may  be  reduced,  also,  by  fusing  it  with 


SILVER — SALTS  OF  SILVER. 


87 


seventy  per  cent  of  chalk,  together  with  four  or  five  per 
cent  of  charcoal. 

A  third  method  of  reduction  of  the  chloride,  is  one  which 
is  very  convenient  for  those  who  do  not  possess  a  furnace, 
or  have  the  convenience  of  fusing  ores  or  residues.  Moisten 
the  chloride  with  dilute  hydrochloric  acid,  and  immerse 
a  plate  of  zinc  in  the  moistened  mass  for  several  hours. 
Decomposition  will  gradually  take  place,  the  silver  being 
deposited,  whilst  the  soluble  chloride  of  zinc  is  formed. 
After  the  chloride  has  been  thus  completely  decomposed, 
the  remaining  zinc  is  withdrawn,  and  the  precipitate  is 
washed  with  dilute  hydrochloric  acid,  until  there  is  no 
longer  any  precipitate  formed  in  the  decanted  fluid  by 
means  either  of  ammonia  or  of  sulphide  of  ammonium.  The 
precipitate  is  next  well  washed  with  warm  water.  It  is 
now  in  a  condition  for  being  dissolved  in  nitric  acid. 

Instead  of  precipitating  the  silver  as  chloride,  in  order  to 
separate  it  from  the  copper,  the  solution  is  evaporated  to 
dryness,  and  then  heated  nearly  to  redness.  By  this  pro- 
cess the  nitrate  of  silver  is  fused,  but  suffers  no  other  change ; 
whilst  the  nitrate  of  copper  is  decomposed,  yielding  up  per- 
oxide of  .nitrogen  and  oxygen,  and  leaving  the  insoluble 
black  oxide  of  copper  mixed  with  the  fused  silver  salt.  By 
dissolving  a  small  portion  of  the  fused  mass  from  time  to 
time  in  water,  and  testing  the  solution,  after  filtration,  with 
ammonia,  it  can  easily  be  ascertained  whether  jt  be  free 
from  copper  or  not.  As  soon  as  no  copper  is  indicated,  the 
fused  mass  is  dissolved  in  pure  water  and  separated  from 
the  insoluble  residue,  evaporated  and  crystallized. 

The  oxide  of  copper  may  be  separated  from  the  nitrate 
of  copper  in  the  solution  by  substitution  of  oxide  of  silver. 
This  oxide  of  silver  is  obtained  by  precipitating  a  quantity 
of  the  given  solution  by  a  solution  of  potassa.  The  collected 
precipitates  of  oxide  of  copper  and  of  oxide  of  silver,  are  then 
well  washed,  and  afterward  boiled  with  the  remaining  parts 
of  the  impure  nitrate.  The  solution  is  then  finally  separated 
from  the  residue,  evaporated  and  crystallized. 

Finally,  the  mixed  solution  may  be  treated  with  plates 
of  copper,  whereby  the  silver  is  precipitated  in  a  state  of 
very  fine  division,  which  is  afterward  obtained  on  the  filter, 
and  thoroughly  purified  by  washing.  This  silver  is  then 
treated  with  pure  nitric  acid  until  dissolved ;  the  solution 
is  then  evaporated  to  dryness,  redissolved,  evaporated  and 
crystallized. 

In  every  case  where  the  salt  thus  obtained  is  intended  for 


88 


SILVER — SALTS  OF  SILVER. 


photographic  purposes,  the  crystals  when  thoroughly  dried 
are  dissolved  in  pure  water,  and  again  crystallized ;  or  the 
solution  of  the  crystals  is  boiled  for  some  time  in  a  glass 
flask  containing  fragments  of  pure  silver,  or  perfectly  well- 
washed  oxide  of  silver,  (procured  as  just  indicated.)  In  this 
way  the  nitrate  of  silver,  after  evaporation  and  crystalliza- 
tion, can  be  had  in  an  absolute  neutral  condition^ 

The  mother-liquor  remaining  after  the  crystals  have  been 
removed,  is  evaporated  to  dryness,  fused  and  poured  into 
cylindrical  moulds  of  the  size  of  a  quill.  In  this  form  it  is 
denominated  lunar  caustic,  and  used  principally  by  sur- 
geons for  cauterizing  erysipelatous,  ulcerated,  etc.,  surfaces. 
From  this  mode  of  its  manufacture,  it  can  not  always  be 
relied  upon  by  the  photographer  as  pure.  In  fact  it  fre- 
quently blackens  by  exposure  to  light,  whilst  pure  crystal- 
lized nitrate  of  silver,  does  not  change  by  a  similar  exposure. 
In  addition  to  impurities  of  an  organic  nature,  it  frequently 
contains,  besides,  nitrite  of  silver,  produced  by  the  decom- 
position of  the  nitrate  by  the  heat  of  fusion. 

Properties, 

Nitrate  of  silver  crystallizes  in  colorless  square  tables  ; 
it  is  an  anhydrous  salt,  and  neutral  when  carefully  prepared. 
This  salt  may  be  fused,  as  before  mentioned,  into  lunar  caus- 
tic; but  if  the  heat  be  too  great,  it  is  decomposed  into  nitrite 
of  silver,  6xygen  being  liberated ;  and  by  a  still  greater  heat 
the  nitric  acid  is  entirely  removed,  and  pure  silver  left  be- 
hind. Nitrate  of  silver  dissolves  in  one  part  of  cold  water, 
and  in  less  of  boiling  water.  It  is  soluble  also  in  about  four 
parts  of  alcohol.  The  oxide  of  the  nitrate  of  silver,  is  pre- 
cipitated by  any  of  the  alkalies  or  alkaline  earths.  In  am- 
monia, added  in  excess,  the  oxide  is  redissolved,  forming  a 
definite  compound  of  the  formula  AgO,  N05,  2NH3,  denom- 
inated ammonio-nitrate  of  silver,  which  by  evaporation  is 
obtained  in  the  crystalline  form. 

Photographic  Properties  of  the  Nitrate  of  Silver. 

Collodion  iodized  with  a  solution  of  iodide  of  silver  in 
iodide  of  potassium  does  not  produce  a  picture  when  ex- 
posed and  developed  by  the  ordinary  process  ;  nor  is  a  col- 
lodion film,  when  sensitized  in  the  bath  of  nitrate  of  silver, 
and  carefully  washed  in  the  dark-room  after  the  operation  of 
sensitizing,  any  longer  as  sensitive  to  the  actinic  influence 
as  before ;  or  supposing  it  to  be  so,  it  no  longer  yields  a 
picture  by  ordinary  development.    It  is,  therefore,  not  the 


SILVER  SALTS  OF  SILVER. 


89 


iodide  of  silver  alone  which  undergoes  the  actinic  impres- 
sion, but  the  iodide  in  connection  with  the  nitrate  of  silver, 
or  the  nitrate  of  the  new  base,  and  probably  with  free  nitric 
acid,  which  is  easily  broken  up  or  decomposed,  and  yields 
thus  its  oxygen  to  produce  or  induce  further  decompositions. 
Whatever  the  theory  or  the  true  explanation  of  the  photo- 
graphic impression  on  the  iodides  or  bromides  may  be, 
whether  physical,  chemical,  electrical,  or  mixed,  that  is, 
T3hysico-chemical,  etc.,  one  thing  as  yet  is  quite  certain, 
(and  this  is  certainly  the  beginning  of  knowledge,)  that  the 
rationale  of  actinism  on  any  substance  or  surface  is  a  mystery, 
has  not  been  hitherto  explained  on  unexceptional  grounds, 
is  not  satisfactorily  deduced  from  experiments.  It  is  useless 
then  to  give  a  long  dissertation  on  a  mere  hypothesis.  But 
we  do  know,  if  not  with  certainty,  at  least  nearly  so,  by 
what  conditions  the  best  results  can  be  obtained  in  refer- 
ence to  the  nitrate  of  silver  bath  in  combination  with  the 
iodized  or  bromo-iodized  collodion.  For  instance,  collodion 
containing,  amongst  other  chemical  ingredients,  free  iodine, 
indicates  at  once  that  the  silver-ba*h  may  be  neutral,  even 
slightly  alkaline  ;  whilst  if  the  collodion  be  new,  contain  no 
free  iodine  or  bromine,  be  colorless,  then  the  bath  appro- 
priate for  producing  a  good  picture  must  be  the  very  con- 
trary of  the  preceding,  it  must  be  slightly  acid.  We  know 
that  acids  retard  the  action  of  development,  limit  this  action 
to  the  parts  impressed  actinically,  prevent  in  consequence 
what  is  denominated  fogging.  We  know,  moreover,  from 
repeated  experiments,  that  it  is  immaterial  whether  the  col- 
lodion or  the  silver-bath  be  slightly  acid,  the  result  is  the 
same,  the  production  of  a  clear  picture  accompanied  with 
the  disadvantage  of  lengthening  the  time  of  action.  But  we 
do  not  yet  know  the  exact  conditions  of  collodion  and  bath 
by  which  clearness  and  sensitiveness  can  be  attained  in  a 
maximum  degree  in  the  shortest  time  without  exception. 

The  iodide  of  silver,  whether  produced  by  the  decomposi- 
tion of  iodide  of  cadmium,  of  lithium,  or  of  any  other  base, 
is.  in  all  probability,  equally  sensitive  ;  but  this  sensitiveness 
is  found  to  be  materially  changed  by  the  presence  of  the 
other  salt  in  the  decomposition.  From  experiments  in  this 
direction  it  is  known  that  the  greatest  degree  of  sensitive- 
ness is  arrived  at  when  the  collodion  contains  iodide  of  iron, 
and  this  probably  because  the  proto-nitrate  of  iron  is  very 
unstable  and  easily  broken  up.  With  such  an  iodizer,  how- 
ever, the  silver-bath  would  soon  be  entirely  deteriorated  by 
the  continual  introduction  of  a  developing  material ;  so  that 


90 


SILVER  SALTS  OF  SILVER. 


many  points  have  to  be  taken  into  consideration  before 
normal  conditions  can  be  isolated  or  legitimate  deductions 
drawn. 

Preparation  of  other  Salts  of  Silver, 

Other  Salts  of  Silver. — Sulphate  of  Silver. — This  salt  is 
obtained  by  dissolving  silver  in  concentrated  sulphuric  acid 
by  the  aid  of  heat ;  or  by  double  decomposition  of  nitrate  of 
silver  with  sulphate  of  soda.  Sulphate  of  silver  is  soluble  in 
eighty-eight  times  its  weight  of  boiling  water,  from  which 
it  crystallizes  on  cooling.  Like  the  nitrate  it  is  anhydrous, 
and  forms  in  like  manner  a  distinct  and  definite  combination 
with  ammonia,  whose  equivalent  is  Ag  O.  S03  +  2  NH3  in 
fine  transparent  crystals. 

Hyposulphite  of  Silver. — This  combination  is  obtained  by 
the  double  decomposition  of  an  alkaline  hyposulphite  and 
nitrate  of  silver.  For  instance,  add  a  dilute  solution  of 
hyposulphite  of  soda  to  a  similar  one  of  nitrate  of  silver  ;  » 
white  precipitate  is  formed  which  is  soon  dissolved  in  the 
menstruum ;  after  a  while,  when  the  hyposulphite  of  soda 
has  dissolved  the  newly  formed  precipitate  to  saturation,  a 
flocculent  substance  is  formed  of  a  dull  gray  color,  which  is 
permanent.  This  second  precipitate  is  hyposulphite  of  sil- 
ver in  an  isolated  state.  But  the  hyposulphite  of  soda  con- 
tains a  large  quantity  also,  thus  giving  rise  to  a  soluble 
double  salt,  which  has  a  very  sweet  taste.  Hyposulphurous 
acid  has  a  very  powerful  affinity  for  silver,  so  that  hydro- 
chloric acid  or  a  soluble  chloride  produces  no  precipitate  in 
the  solution-  of  the  double  salt  of  hyposulphite  of  silver  and 
of  soda.  In  such  a  solution,  containing  a  large  proportion 
of  waste  silver,  the  best  way  to  obtain  or  separate  the  silver 
is  to  pass  a  current  of  hydrosulphuric  acid  through  the  solu- 
tion, in  order  that  the  silver  may  be  precipitated  as  sulphide 
of  silver.  Hyposulphite  of  silver  undergoes  spontaneous 
decomposition  into  sulphate  and  sulphide  of  silver ;  on  this 
account  the  fixing-bath  is  found  to  contain  in  general  a  large 
quantity  of  black  sediment,  which  is  sulphide  of  silver.  This 
sulphide,  when  a  sufficient  quantity  has  been  collected,  is  re- 
duced by  heat  into  sulphurous  acid  and  metallic  silver. 

Iodide  of  Silver. — This  salt  is  found  native,  and  some- 
times in  the  form  of  hexagonal  prisms.  It  may  be  formed 
artificially  by  allowing  the  vapor  of  iodine  to  play  upon 
polished  plates  of  silver,  as  in  the  Daguerreotype  process,  or 
by  double  decomposition.  When  excess  of  nitrate  of  silver 
in  solution  is  added  to  a  solution  of  iodide  of  potassium  or 


SILVER — SALTS  OF  SILVER. 


91 


to  hydriodic  acid,  a  yellow  precipitate  is  produced  ;  this  is 
iodide  of  silver ;  whereas  if  the  iodide  of  potassium,  be  in 
excess,  the  precipitate  is  nearly  white,  its  soluble  and  yellow 
part  having  been  dissolved  by  the  alkaline  iodide.  The 
yellow  precipitate  is  that  form  of  the  iodide  which  is  best 
adapted  for  photographic  purposes.  It  is  insoluble  in  water 
and  in  dilute  nitric  acid  ;  almost  insoluble  in  ammonia  ;  and 
is  not  so  soon  colored  by  the  action  of  light  as  the  chloride. 
It  is  very  soluble  in  the  alkaline  iodides,  in  cyanide  of  potas- 
sium, and  hyposulphite  of  soda,  and  by  evaporation  may  be 
crystallized  out  of  them  as  double  iodides,  etc.  When  silver 
is  dissolved  in  hydriodic  acid,  crystals  of  the  iodide  of  silver 
may  be  obtained  in  the  solution  by  spontaneous  evaporation. 
Iodide  of  silver  may  be  reduced  in  the  same  way  as  the 
chloride  by  means  of  zinc.  Hydrochloric  acid  converts  it 
into  chloride  of  silver.  It  is  decomposed  by  both  chlorine 
and  bromine  which  liberate  iodine.  It  is  soluble  to  a  small 
extent  in  solution  of  nitrate  of  silver. 

Iodide  of  Silver  for  the  Silver-JBath. — Add  to  a  small 
quantity  of  iodide  of  potassium  in  solution  a  larger  quantity 
of  dissolved  nitrate  of  silver ;  allow  the  canary-yellow  colored 
precipitate  to  subside  ;  decant  the  supernatant  liquid ;  wash 
with  water  and  again  decant,  and  repeat  the  washing  several 
times.  Let  this  operation  be  performed  in  the  dark-room. 
The  yellow  precipitate,  whilst  still  moist,  is  added  to  the 
bath  of  nitrate  of  silver  in  proper  quantity  as  long  as  it  is 
dissolved  by  the  same  ;  the  solution  is  then  filtered  ;  and  as 
regards  saturation  with  the  iodide  of  silver,  is  ready  for 
use. 

Bromide  of  Silver, — This  salt  is  found  native  in  Mexico 
and  in  Bretagne,  sometimes  in  an  amorphous  condition,  and 
sometimes  crystallized  of  a  greenish-yellow  color.  It  is 
formed  artificially  by  exposing  plates  of  silver  to  the  vapor 
of  bromine,  or  by  decomposing  nitrate  of  silver  by  an  alka- 
line, or  any  other  soluble  bromide.  The  precipitate  is  white 
at  first,  but  becomes  yellow  afterward.  It  may  be  fused,  and 
when  cool  its  color  is  intensely  yellow.  Bromide  of  silver 
is  very  sensitive  to  light,  but  the  color  when  so  acted  upon 
by  light  is  very  different  from  that  of  the  chloride.  It  is 
soluble  in  strong  ammonia  and  in  chloride  of  ammonium,  as 
also  in  hyposulphite  of  soda  and  cyanide  of  potassium.  The 
bromides  are  decomposed  by  chlorine,  whereby  bromine  is 
liberated,  and  maybe  collected  by  ether,  which,  by  agitation, 
collects  the  bromine  and  carries  it  to  the  surface,  from  which 
it  may  be  decanted. 


92 


SILVER — SALTS  OF  SILVER. 


Chloride  of  Silver. — Next  to  the  nitrate  of  silver,  the 
chloride  is  perhaps  the  most  important  combination  of  this 
metal.  It  occurs  native  as  horn-silver  in  translucent  cubes 
or  octohedra  of  a  grayish- white  color ;  its  specific  gravity 
in  the  native  form  is  5.55.  Like  the  iodide  and  bromide  of 
silver,  it  may  be  obtained  by  exposing  plates  of  silver  to  the 
vapor  of  chlorine.  The  surface  of  the  plates  soon  becomes 
covered  with  a  chalky  film,  which  is  the  chloride  in  ques- 
tion. It  is  obtained  as  an  insoluble  white  powder  by  de- 
composing nitrate  of  silver,  or  any  other  solution  of  silver 
excepting  the  hyposulphite,  by  means  of  hydrochloric  acid 
or  a  soluble  chloride,  by  which  a  complete  interchange  takes 
lace,  and  a  dense  curdy  precipitate  falls  gradually  to  the 
ottom.  After  subsidence  the  liquid  is  poured  off,  and  the 
residue  is  well  washed  in  several  waters.  This  operation 
must  be  performed  in  the  dark-room,  because  the  chloride 
of  silver  is  very  sensitive  to  light,  and  soon  changes  from  a 
white  to  a  violet  color  in  the  sun  or  in  diffused  light.  This 
violet-colored  substance  is  a  sub-chloride  or  an  oxy-chloride, 
and  may  be  formed  directly  by  chemical  means  as  follows :  dip 
a  plate  of  polished  silver  into  a  solution  of  sesqui-chloride 
of  iron,  or  of  bichloride  of  mercury ;  the  surface  becomes 
stained  black;  the  iron  or  mercury  parting  with  a  portion  of 
its  chlorine,  is  reduced  to  a  lower  chloride,  whilst  the  silver 
film  becomes  converted  into  a  sub-chloride  of  silver.  Chlo- 
ride of  silver  is  insoluble  in  water  ;  it  is  very  soluble  in  am- 
monia, in  cyanide  of  potassium,  in  hyposulphite  of  soda,  as 
also  in  concentrated  and  boiling  solutions  of  chloride  of 
potassium,  chloride  of  sodium,  and  chloride  of  ammonium, 
from  which  may  be  obtained,  by  evaporation  in  one  case 
and  by  cooling  in  the  other,  crystals  of  double  salts  of  chlo- 
ride of  silver  and  the  other  substances  in  the  solvents.  Hy- 
drochloric acid  in  a  very  concentrated  state  dissolves  a 
minute  quantity  of  chloride  of  silver,  which  crystallizes  on 
evaporation  of  the  acid.  It  is  precipitated  from  all  solutions 
of  silver  salts,  as  before  mentioned,  except  from  hyposulphite 
of  silver,  by  means  of  hydrochloric  acid.  At  a  temperature 
of  500°  Fahr.  it  fuses  into  a  transparent  yellowish  fluid, 
which  when  cool  may  be  cut  with  a  knife  like  a  piece  of 
horn,  and  has  beside  some  other  resemblance  to  horn ;  it 
hence  received  the  name  of  horn-silver  by  the  older  phar- 
maceutists. Chloride  of  silver  can  not  be  volatilized  like  the 
protochloride  of  mercury.  The  mode  of  its  reduction  into 
pure  silver  by  two  or  three  different  processes  has  already 
been  given  under  the  head  of  Silver.    It  may  be  reduced 


SILVER  SALTS  OF  SILVER. 


93 


also  by  a  mixture  of  carbonate  of  potassa,  cane-sugar,  or 
starch-sugar  and  water. 

Tests  :  Chloride  of  silver  is  distinguished  from  all  other 
precipitates,  having  the  same  color,  by  the  property  which 
it  possesses,  when  exposed  on  a  white  saucer  or  evaporat- 
ing-dish,  of  becoming  changed  into*  a  violet-colored  sub- 
stance. Its  insolubility  in  nitric  acid,  and  solubility  in  am- 
monia, is  also  an  excellent  test  when  combined  with  the 
preceding. 

Photographic  Properties  of  Chloride  of  Silver. 

There  is  quite  an  analogy  in  the  application  of  iodide  of 
silver  and  chloride  of  silver ;  the  former  being  essentially  in 
combination  with  a  nitrate  or  free  nitric  acid,  the  sensitive 
collodion  film ;  whilst  the  latter,  in  combination  likewise 
with  a  nitrate  or  free  nitric  acid,  forms  the  sensitive  film 
on  gelatine,  albumen,  arrow-root,  resinized,  gutta-percha,  or 
plain  paper.  These  papers  have  first  imbibed,  or  have  been 
invested  with,  certain  soluble  chlorides,  as  of  ammonium, 
sodium,  etc.,  by  floating  or  otherwise,  and  then  dried.  By 
double  decomposition  afterward  these  chlorides  are  con- 
verted, by  floating  the  papers  on  a  solution  of  nitrate  of 
silver,  into  chloride  of  silver.  Organic  salts  of  silver  are 
formed  simultaneously,  such  as  the  albuminate,  etc.,  which 
assist  in,  or  detract  from,  the  photographic  operation.  Of 
this  I  shall  speak  more  extensively  when  I  have  to  discuss 
the  theory  and  practice  of  Positive-printing  on  paper. 

Other  Uses  of  Chloride  of  Silver.  —  The  solution  used 
in  galvano-plasty,  or  electrolysis,  for  plating  with  silver  is 
made  by  dissolving  in  a  saturated  solution  of  cyanide  of 
potassium  the  moist  and  undecomposed  chloride  of  silver  to 
saturation,  and  then  diluting  this  solution  by  four  or  five 
times  its  bulk  of  water. 

The  grayish-colored  powder  used  for  dry-plating  or  for 
silvering  dial-plates,  thermometer-scales,  etc.,  consists  of 
one  part  of  chloride  of  silver,  five  parts  of  cream  of  tartar, 
and  four  of  common  salt,  rubbed  on  with  a  piece  of  flannel 
or  sponge  dipped  in  solution  of  salt. 


CHAPTER  XIV. 


REDUCING  AGENTS — DEVELOPERS. 

As  already  remarked  in  a  preceding  chapter,  the  actinic  im- 
pression of  an  object  on  the  prepared  collodion  film  is  invisible 
or  latent ;  it  is  like  the  impression  of  the  finger  on  a  plate  of 
copper,  or  of  a  warm  piece  of  metal  on  a  glass  mirror ;  after 
the  removal  of  the  finger,  or  of  the  metal,  the  eye  can  not 
distinguish  the  spot  where  the  impression  was  made ;  but,  as 
Moeser  first  illustrated,  breathing  upon  the  glass  will  make 
the  impression  manifest,  will  show  that  the  image  was  there 
in  a  latent  or  invisible  condition.  In  like  manner  a  plate  of 
polished  silver  may  be  substituted  for  the  glass  mirror,  and 
excised  metallic  figures  be  placed  when  warm  on  its  sur- 
face ;  the  impression  is  quite  invisible,  but  becomes  visible 
when  the  silver  plate  is  exposed  to  the  vapor  of  mercury. 

Furthermore,  if  the  glass  mirror,  or  the  polished  metallic 
plate  be  exposed  in  the  camera  before  an  object,  and  the  for- 
mer be  breathed  upon,  and  the  latter  exposed  to  the  vapor 
of  mercury,  in  either  case  the  picture  becomes  visible  ;  but 
the  picture  in  either  case  is  a  mere  breath,  an  evanescent 
shadow.  It  gives  us,  however,  a  distinct  idea  of  what  is 
meant  by  a  developer,  it  is  the  prototype  of  a  reducing  agent. 
In  chemistry  is  understood  by  a  reducing  agent,  a  substance, 
which,  when  applied  to  a  combination,  properly  speaking  of 
a  metal,  will  decompose  the  compound  in  such  a  way  as  to 
leave  the  metal  in  the  reguline  condition,  isolated  from  the 
other  combining  materials.  Hydrogen  and  carbon  are  the 
best  chemical  reducing  agents.  Pass  a  current  of  hydrogen 
through  a  glass  tube  containing  oxide  of  copper  heated  to 
redness ;  in  this  state  the  hydrogen  has  more  affinity  for  the 
oxygen  of  the  oxide  than  the  copper  possesses ;  the  two  me- 
talloids therefore  pair  and  pass  off  in  combination  as  the  va- 
por of  water,  leaving  the  copper  reduced  to  the  metallic  state. 
A  solution  of  nitrate  of  silver,  impressed  by  blocks  upon  silk, 
is  reduced  to  a  bright  film  of  silver  when  exposed  to  hy- 
drogen gas.    Heat  a  mixture  of  charcoal  and  oxide  of  lead 


REDUCING  AGENTS — DEVELOPERS. 


95 


in  a  crucrble,  carbonic  acid  results  from  the  combination  of 
charcoal  and  oxygen,  whilst  the  metal  lead  is  reduced.  Elec- 
tricity, Heat  and  Light  are  all  reducing  agents.  Fill  a  tum- 
bler with  the  solution  of  chloride  of  silver  in  cyanide  of  potas 
sium,  just  above  mentioned.  Next  take  two  copper  wires, 
to  the  end  of  one  solder  a  quarter  of  a  dollar,  to  the  other 
attach  on  a  hook  any  clean  and  well-polished  article  of  brass 
or  copper  ;  the  other  end  of  the  latter  wire  is  now  fastened 
to  the  negative  or  zinc  side  of  a  galvanic  battery,  whilst  the 
end  of  the  other  copper  wire  is  fixed  on  the  positive  or  pla- 
tinum side  of  the  battery.  Insert  the  piece  of  silver  and  the 
brass,  etc.,  object  in  the  tumbler,  but  not  in  contact ;  the  sil- 
ver in  the  solution  will  immediately  begin  to  be  reduced,  and 
by  the  electrical  current,  will  be  carried  to  the  negative  side 
and  deposited  on  the  object  to  be  plated. 

By  heat  alone  several  of  the  oxides  are  reduced  to  the  me- 
tallic state,  as  for  instance,  oxide  of  mercury,  of  silver,  etc. 
Some  are  reduced  by  light,  as  those  of  gold. 

Many  of  the  salts  of  the  metals  are  reduced  by  the  supe- 
rior affinity  of  other  metals.  Immerse  a  piece  of  copper  wire 
in  a  solution  of  nitrate  of  mercury ;  nitrate  of  copper  will  be 
formed  and  mercury  precipitated  on  the  copper.  Mercury 
precipitates  silver  from  nitrate  of  silver ;  zinc  precipitates 
lead  from  the  acetate  of  this  metal,  and  iron  precipitates  cop- 
per from  its  nitrate. 

Potassium  and  sodium  by  their  very  superior  attraction 
for  oxygen  are  regarded  as  among  the  best  reducing  agents  ; 
cyanide  of  potassium  unites  the  properties  of  carbon  and  po- 
tassium in  the  way  of  reduction.  The  protosalts  of  iron  are 
easily  changed  into  the  persalts  when  brought  into  contact 
with  oxides  in  which  the  oxygen  has  been  loosened  in  its  af- 
finities, or  when  in  contact  with  chlorine  or  nitric  acid ;  and 
the  metallic  base  is  precipitated.  Tannic  acid,  gallic  acid, 
pyrogallic  acid  and  formic  acid  are  all  excellent  reducers. 
The  last  substances  enumerated  are  those  in  general  use  as 
reducers  or  developers  in  photography  ;  but  the  substance  re- 
duced or  precipitated  by  them  is  not  always  a  pure  metal ; 
in  some  instances  it  appears  pure  and  metallic,  in  others  bla^k 
and  free  from  metallic  lustre,  as  if  it  were  mixed  with  organic 
material.  The  act  of  reduction  in  photography  consists  in 
reducing  a  silver  compound ;  this  reduction  is  aided  by  the 
presence  of  nitric  acid  or  a  nitrate  ;  without  nitric  acid  or 
a  nitrate  the  development  in  question  seems  impossible,  and 
it  is  equally  impossible  without  the  previous  action  of  light. 
Now  let  us  see  what  the  action  of  the  protosulphate  of  iron 


96 


REDUCING  AGENTS — DEVELOPERS. 


is  upon  the  oxide  of  silver  in  solution,  as  also  of  nitric  acid 
upon  the  protosulphate  of  iron.  In  the  first  place  dissolve  a 
crystal  of  green  vitriol  in  a  drop  or  two  of  nitric  acid :  decom- 
position ensues  ;  the  nitric  acid  is  broken  up  into  parts,  fumes 
of  the  peroxide  of  nitrogen  are  liberated,  and  a  reddish  col- 
lored  persulphate  of  iron  is  produced  from  the  absorption  of 
oxygen.  Secondly,  dissolve  a  small  quantity  of  the  oxide  of 
silver  in  nitrate  of  ammonia,  and  add  solution  of  the  proto- 
sulphate of  iron  to  the  ammonio -nitrate.  The  mixed  solution 
becomes  colored  and  turbid,  and  a  deposit  subsides,  which 
is  found  to  be  pure  silver. 

By  experience  we  know  that  the  film  on  a  collodion  plate, 
after  development  with  protosulphate  of  iron,  is  also  pure  sil- 
ver, soluble  in  nitric  acid.  Now  coupling  the  two  facts  together 
that  both  light  and  nitric  acid  are  required  before  the  reduc- 
tion can  take  place,  and  also  that  there  must  be  present  the 
oxide  of  silver  in  solution,  (for  the  reduction  is  ineffectual 
with  the  iodide  of  silver,)  it  seems  as  if  we  were  indicated  to 
believe  that  the  action  of  light  produced  an  oxide  in  all  those 
parts  where  it  struck,  or  loosened  the  oxide  of  the  nitrate  of 
silver  present  on  the  film,  wherever  the  actinic  rays  made  an 
impression.  This  loosening  of  the  oxide  of  silver  from  its 
connection  with  the  acid  may  be  effectuated  by  the  conjoint 
action  of  light  and  iodine  or  bromine,  whereby  a  double  de- 
composition is  instituted  the  very  reverse  of  that  which  or- 
dinarily takes  place,  that  is,  iodide  of  silver  and  nitrate  of 
potassa  are  reconverted  by  light  into  iodide  of  potassium  and 
nitrate  of  the  oxide  of  silver  in  the  act  of  formation,  or  prop- 
erly speaking,  into  nitric  acid  and  oxide  of  silver,  held  in 
abeyance  by  some  power  (light  or  electricity)  which  pre- 
vents their  union.  If  this  were  so,  it  seems  to  me,  we  have 
an  assemblage  of  materials  in  the  right  condition  for  pro 
ducing  the  effects  which  in  reality  take  place.  With  such 
circumstances  and  conditions  it  is  easy  to  see  how  a  solution 
of  protosulphate  of  iron  would  reduce  the  oxide  of  silver  into 
a  film  of  pure  silver,  whose  thickness  would  vary  as  the  in- 
tensity of  the  actino -chemical  action.  There  is  no  absurdity 
in  supposing  the  possibility  of  the  inversion  alluded  to.  The 
vapor  of  water,  by  passing  through  an  iron  or  porcelain  tube 
heated  to  a  white  heat,  is  decomposed  into  its  elements ; 
whereas  if  the  heat  of  flame  be  applied  to  a  mixture  of  these 
gases,  they  recombine  instantaneously  and  reproduce  the 
vapor  of  water.  Other  analogous  inversions  of  chemical  af- 
finity are  known  to  the  chemist. 


REDUCING  AGENTS — DEVELOPERS. 


97 


Iron  Developer. 

Iron. — Symbol,  Fe.  Combining  Proportion,  28.  Spec.  Grav.,  7.8 

Protoxide  of  Iron.— Symbol,  FeO.       "  "  36. 

Sesquioxide  of  Iron.— Symbol,  Fe2  03.  "  "  80. 

With  iron,  as  with  some  metals,  we  have  two  classes  ot 
salts,  the  protosalts  and  the  persalts,  that  is,  the  salts  of  the 
protoxide  and  the  salts  of  the  peroxide.  The  two  classes 
are  not  equally  permanent,  sometimes  the  protosalts  being 
the  stable  salts,  and  sometimes  the  other.  Those  salts  which 
are  not  stable  are  liable  to  part  with  their  oxygen,  or  to  take 
up  more  oxygen,  according  to  their  condition  of  stability. 
Thus  it  happens  with  the  iron  compounds.  The  protoni- 
trate,  for  instance,  is  changed  by  boiling  into  a  salt  of  the 
sesquioxide ;  and  the  proto-sulphate  is  apt  to  undergo  decom- 
position and  assume  a  coppery  appearance,  by  changing  into 
the  persalt.  This  property  in  salts  and  acids  of  communicat- 
ing to,  or  of  abstracting  oxygen  from  other  chemical  substances 
in  contact  with  them  is  made  available  in  various  reactions ; 
as,  for  instance,  in  toxicological  investigations,  arsenic  acid  is 
reduced  by  sulphurous  acid  into  arsenious  acid  ;  on  this  ac- 
count sulphurous  acid  is  properly  called  a  reducing  agent. 
In  photography,  as  already  remarked,  the  sulphate  of  the 
protoxide  of  iron  passes  easily  into  the  sesquisalt,  by  ab- 
stracting oxygen  from  somewhere,  whereby  a  picture  on  the 
collodion  film  becomes  visible. 

Nitrate  of  the  Protoxide  of  Iron. 

Symbol,  FeO,  N  05. 

This  substance  is  obtained  best  by  decomposing  the  sul- 
phate by  means  of  nitrate  of  baryta.  The  solution  has  a  green 
color,  like  all  the  protosalts ;  it  can  not  easily  be  crystallized, 
because  a  high  temperature  decomposes  it  into  a  sesquisalt. 

Sulphate  of  the  Protoxide  of  Iron. 

Symbol,  Fe  0,  S  O3,  H  0  +  6  Aq.    Combining  Proportion,  139. 

Sulphate  of  iron  is  obtained  by  dissolving  iron  to  satura- 
tion in  a  dilute  solution  of  sulphuric  acid,  decanting  the  su- 
pernatant liquid,  evaporating  and  setting  aside  for  crystalliza- 
tion. These  crystals  have  a  slightly  bluish-green  color.  When 
exposed  to  the  air  the  crystals  become  colored  of  a  brick- 
red  color,  by  decomposition ;  and  if  the  crystals  be  exposed 
to  a  temperature  of  212°  Fahr.,  or  a  little  upwards,  they  part 
with  the  six  equivalents  of  the  water  of  crystallization,  and 


98 


REDUCING  AGENTS — DEVELOPERS. 


crumble  into  a  grayish-white  powder  ;  at  a  higher  tempera- 
ture the  remaining  equivalent  of  water  may  be  expelled.  It 
is  from  the  anhydrous  salt  now  left  that  anhydrous  sulphu- 
ric acid  is  obtained,  or  at  least  the  very  strong  and  fuming 
sulphuric  acid  of  Nordhausen.  In  the  preparation  of  this 
acid  from  the  residual  salt  above  mentioned,  a  high  temper- 
ature is  required,  by  which  the  affinity  of  the  acid  for  the 
base  is  destroyed,  and  is  expelled,  leaving  in  the  retort  a 
pulverulent  red  mass,  the  colcothar  of  the  alchemists,  or  ses- 
quioxide  of  iron.  Sulphate  of  iron  is  soluble  in  two  parts  of 
cold  water  and  three  fourths  of  a  part  of  boiling  water ;  the 
solution  is  neutral.  This  salt  is  not  soluble  in  alcohol ;  if  al- 
cohol be  added  to  a  solution  of  sulphate  of  iron,  the  salt  is 
precipitated  in  a  Avhite  granular  form,  which  is  very  conve- 
nient for  photographic  purposes  ;  by  this  process  it  is  purified 
from  any  superfluous  acid  which  it  may  contain. 

Double  Sulphate  of  Iron  and  Ammonia. 

It  has  been  proposed  by  Meynier  to  substitute  this  double 
salt  for  the  protosulphate  of  iron,  because  of  its  permanency 
when  exposed  to  the  air,  or  its  less  liability  to  decomposi- 
tion.   This  double  salt  was  described  by  Mitscherlich. 

Preparation. 

Take  equivalent  proportions  of  sulphate  of  iron  and  sul- 
phate of  ammonia,  that  is,  139  parts  of  the  former  to  15  oi 
the  latter,  and  dissolve  the  salts  in  four  or  five  parts  of  water  ; 
when  the  solution  is  complete,  filter  and  evaporate,  and  af- 
terward set  aside  to  crystallize.  The  solution  for  photo- 
graphic purposes  can  be  prepared  in  quantity,  and  it  keeps 
well  without  undergoing  much  change.  The  formula  for 
development  with  this  double  salt  does  not  differ  from  the 
simple  protosulphate ;  it  contains  alcohol,  water,  and  acetic 
acid. 

Sulphide  of  Iron. 

Symbol,  Fe  S.    Combining  Proportion,  44. 

This  substance  is  not  used  directly  in  any  photographic  ope- 
ration ;  but  for  the  chemist  and  experimental  photographer 
it  has  great  value,  because  it  assists  in  the  formation  of  hy- 
drosulphuric  acid,  which  is  by  far  the  most  valuable  reagent 
in  chemistry. 

Preparation. 

Heat  a  bar  of  iron  in  a  blacksmith's  forge  to  a  welding 
heat,  and  then  rub  it  on  a  stick  of  sulphur ;  combination  will 


REDUCING  AGENTS — DEVELOPERS. 


99 


take  place  very  vividly,  and  the  new  compound  will  drop  oft 
like  melted  wax.  When  cool  it  has  a  dark  gray  color  and 
metallic  appearance.  Pulverized  and  thrown  into  dilute 
sulphuric  acid,  it  gives  rise  to  hydro-sulphuric  acid,  which 
may  be  collected  or  used  immediately  by  passing  it  through 
a  given  fluid,  as  for  instance,  an  old  hyposulphite  bath,  in 
order  to  reduce  the  silver  in  the  form  of  the  sulphide  of  silver. 

Tannic  Acid —  Gallic  Acid — Pyrogallic  Acid. 

The  first  substance  exists  in  the  vegetable  kingdom,  and 
is  obtained  from  the  astringent  materials  in  various  plants, 
but  especially  from  oak  bark  and  nutgalls,  which  are  ex- 
crescences on  the  leaves  of  an  oak  [quercus  infectoria)  pro- 
duced by  an  insect.  The  second  does  not  exist  naturally, 
or  at  least  in  very  minute  quantity,  but  is  rather  a  produc- 
tion arising  from  tannic  acid  when  exposed  to  moisture  and 
the  atmosphere ;  and  the  third  is  obtained  from  the  second 
by  sublimation  at  a  given  temperature.  The  peculiar  prop- 
erty of  the  astringent  principle  in  various  barks,  is  to  occa- 
sion a  precipitate  in  solutions  of  gelatine,  and  in  several  me- 
tallic salts.  It  produces  in  solutions  of  the  persalts  of  iron  a 
dark  blue  or  dingy  green  color,  according  to  the  bark  from 
which  it  is  extracted.  From  the  property  of  acting  upon 
gelatine,  by  which  skins  are  converted  into  leather,  it  is  de- 
nominated tannin;  and  from  its  power  of  combining  with 
metallic  bases,  and  forming  precipitates,  etc.,  it  is  regarded 
as  an  acid,  and  termed  tannic  acid. 

The  tannin  extracted  from  the  wood,  the  bark,  the  leaves 
and  the  galls  of  oak,  the  twigs  of  the  black  currant  and  of 
the  sumac,  the  petals  of  the  pomegranate,  etc.,  and  from  the 
roots  of  several  plants,  produces  in  solutions  of  the  sesqui- 
salts  of  iron,  a  deep  blue  color,  the  foundation  of  writing-ink. 

Whereas  the  tannin  from  horse-chestnuts,  the  different 
varieties  of  tea,  from  catechu  and  kino,  cinchona  bark,  cin- 
namon, cassia,  etc.,  yields  a  green  precipitate  with  solutions 
of  the  persalts  of  iron. 

Tannic  Acid. — Symbol,  C54H22O34. 
Gallic  Acid.— Symbol,  C14HfiO]0. 
Pyrogallic  Acid. — Symbol,  C6H303. 

Preparation  of  Tannic  Acid. 

Tannic  acid  is  prepared  by  a  process  suggested  by  Pelouze. 
Take  an  elongated  glass  funnel,  terminating  at  the  upper 
orifice  like  a  bottle,  which  can  be  closed  by  a  cork.  The 
lower  orifice  is  loosely  closed  by  a  plug  of  cotton-wool,  or  a 


100 


REDUCING  AGENTS — DEVELOPERS. 


piece  of  sponge ;  the  body  of  the  funnel  is  then  half  filled 
with  powdered  nutgalls,  over  which  is  poured  a  quantity  of 
commercial  ether,  so  as  to  fill  the  remaining  part  of  the  fun- 
nel. The  cork  is  then  replaced  loosely,  admitting  a  little  air 
as  the  filtration  proceeds.  The  liquid  that  passes  through 
the  funnel,  and  accumulates  beneath,  forms  two  layers  ;  the 
upper  one  light  and  very  fluid,  and  the  lower  heavier  and 
of  a  yellowish  tinge.  Ether  is  added  above  the  galls,  from 
time  to  time,  until  the  lower  stratum  of  the  filtrate  no  longer 
increases  in  depth.  The  funnel  is  then  removed  from  the  ves- 
sel beneath,  and  the  lower  stratum  is  separated  by  means  of 
a  glass  syringe  inserted  to  the  bottom ;  or  the  whole  con- 
tents can  be  placed  in  a  funnel,  of  which  the  lower  aperture 
is  closed  by  the  finger.  In  this  way  the  dense  fluid  is 
allowed  to  flow  off,  and  when  the  whole  has  been  thus  re- 
moved, the  aperture  is  again  closed  with  the  finger,  and  the 
light  fluid  is  poured  into  a  retort,  and  distilled  at  a  gentle 
heat.  It  consists  principally  of  ether.  The  dense  fluid  is 
then  washed  with  concentrated  ether,  from  which  it  is  sep- 
arated as  before,  and  afterward  evaporated  at  a  low  tem- 
perature to  dryness.  The  resulting  substance  is  light  and 
spongy,  of  an  ochreous  color.  It  is  pure  tannin  or  tannic 
acid,  in  quantity  about  thirty-five  per  cent  of  the  galls  em- 
ployed. It  has  a  slightly  acid  reaction,  is  very  astringent, 
not  bitter.  It  is  soluble  in  water  and  alcohol,  but  sparingly 
soluble  in  ether.  With  mineral  acids,  albumen,  gelatine, 
salts  of  the  alkaloids,  mineral  bases,  it  forms  precipitates. 
Salts  of  the  protoxide  of  iron  are  not  changed  by  tannic 
acid ;  but  those  of  the  sesquioxide  give  a  deep  bluish-black 
precipitate. 

Tannic  acid  is  used  extensively  in  photography  in  the 
preparation  of  the  dry  plates  by  the  Tannin  Process  of  Ma- 
jor Russell.  This  process  is  fully  described  in  a  subsequent 
chapter. 

Preparation  of  Gallic  Acid. 

As  before  observed,  gallic  acid  exists  in  minute  quantity 
in  nutgalls  ;  but  it  is  rather  a  product  of  the  decomposition 
of  tannin,  than  a  naturally  existing  substance.  Mix  pow- 
dered nutgalls  into  a  thin  paste,  and  expose  it  to  the  air  for 
two  or  three  months,  taking  care  to  replace  the  water  as  it 
evaporates.  The  mass  becomes  mouldy,  and  darker  in  color 
by  this  exposure ;  it  is  then  pressed  in  a  cloth ;  afterward, 
the  residue  is  boiled  in  water  and  filtered  whilst  hot.  On 
cooling,  crystals  of  gallic  acid  are  deposited,  which  are  puri- 


REDUCING  AGENTS  DEVELOPEKS. 


101 


fied  by  boiling  in  eight  parts  of  water  and  one  fifth  of  their 
weight  of  animal  charcoal.  After  filtration  and  cooling,  pure 
crystals  of  gallic  acid  are  deposited,  in  the  form  of  long 
silky  needles.  During  exposure  to  the  atmosphere,  moist 
tannic  acid  absorbs  oxygen,  and  liberates  carbonic  acid,  so 
that  gallic  acid  is  altogether  a  definite  and  distinct  com- 
pound. When  quite  purified,  it  has  no  effect  upon  a  solu- 
tion of  gelatine ;  it  has  an  acid  and  astringent  taste.  The 
solution  is  soon  decomposed.  Gallic  acid  is  soluble  in  one 
hundred  parts  of  cold  water,  and  in  three  of  boiling  water. 
It  has  no  effect  upon  the  solution  of  salts  of  the  protox- 
ide of  iron,  but  upon  those  of  the  sesquioxide,  it  produces 
a  deep  bluish-black  precipitate,  which  disappears  when  the 
liquid  is  heated,  the  sesquioxide  being  converted  into  the 
protoxide  by  the  decomposition  of  the  gallic  acid.  Gallic 
acid  meets  with  an  extensive  application  in  photography,  in 
various  processes,  as  in  the  Tannin  Process  of  Major  Russell, 
the  Dry  Process  of  Taupenot,  etc.,  and  in  the  process  of  Posi- 
tive Printing  by  Development. 

Preparation  of  Pyrogallic  Acid. 

The  etymology  of  the  word  indicates  the  origin  of  this 
substance.  When  gallic  acid  is  heated  to  the  temperature 
of  410°  Fahrenheit,  and  kept  at  this  temperature,  in  an  oil- 
bath,  a  volatile  substance  sublimes  of  a  beautiful  white  color, 
in  crystalline  plates.  This  is  pyrogallic  acid,  which  is  sol- 
uble in  water,  alcohol,  and  ether.  The  solution  of  pyrogallic 
acid  soon  turns  brown  when  exposed  to  the  air,  by  becom- 
ing oxidized.  It  communicates  a  blackish-blue  color  to  the 
solutions  of  the  salts  of  the  protoxide  of  iron,  and  reduces 
those  of  the  sesquioxide  to  the  state  of  the  protoxide.  When 
mixed  with  an  alkaline  solution,  it  absorbs  a  large  quantity 
of  oxygen  from  the  atmosphere,  and  has  been  used  in  the 
analysis  of  air  for  this  special  purpose.  When  gallic  acid  is 
raised  to  a  higher  temperature  than  410°  Fahrenheit,  that  is, 
to  480°  Fahrenheit,  it  is  decomposed  into  carbonic  acid, 
water,  and  a  new  substance  denominated  metagallic  acid, 
being  the  black  shining  residue  left  in  the  retort.  Pyrogal- 
lic acid,  at  the  proper  temperature,  is  in  like  manner  decom- 
posed into  metagallic' acid  and  water. 

Owing  to  the  property  possessed  by  pyrogallic  acid  of  ab- 
sorbing oxygen  from  bodies  with  which  it  is  in  contact,  it  is 
as  yet  the  second  best  developer  of  the  latent  image  in  the 
collodion  process ;  and  taking  into  consideration  the  nature 
of  the  image  produced,  where  the  time  of  exposure  is  not 


102 


REDUCING  AGENTS  DEVELOPERS. 


important,  it  certainly  is  the  most  easy  and  reliable  devel- 
oper. There  is  no  doubt  that  a  solution  of  protosulphate  of 
iron  acts  more  quickly ;  or,  what  is  meant,  requires  a  much 
shorter  time  of  exposure.  From  the  experiments  in  ordi- 
nary landscape  photography,  I  have  frequently  observed  a 
difference  of  three  to  one  in  the  time  in  favor  of  the  sul- 
phate of  the  protoxide  of  iron. 

Acids  in  Developing  Solutions. 

The  solution  of  protosulphate  of  iron,  or  of  pyrogallic 
acid,  is  frequently  much  more  energetic  in  reduction  than  is 
manageable,  and  proceeds,  after  the  image  has  been  thor- 
oughly developed,  to  act  upon  those  parts  on  which  the 
actinic  influence  has  been  but  very  feeble  or  almost  imper- 
ceptible. The  difficulty  in  such  a  case  is  two-fold.  It  con- 
sists in  flowing  the  plate  uniformly  and  instantaneously; 
otherwise  lines  of  demarkation  will  be  quite  visible  at  those 
edges  where  the  fluid  was  momentarily  retarded ;  and  sec- 
ondly, in  stopping  the  progress  of  development  uniformly 
and  instantaneously.  Many  excellent  negatives  have  been 
ruined  by  the  misfortunes  arising  from  the  difficulties  alluded 
to  ;  and  yet  Instantaneous  Photography  has  to  search  in  this 
direction  for  the  surest  means  of  success,  rather  than  upon 
any  fortuitous  advantages  in  the  collodion.  The  operation  of 
light  is,  practically  speaking,  instantaneous,  because  its  ve- 
locity is  greater  than  conception.  A  certain  time  always 
elapses  between  the  opening  and  closing  of  the  shutter,  be- 
fore the  lenses,  in  the  operation  of  instantaneity ;  and  in  this 
time  light  has  traveled  thousands  of  miles,  or  rushed  with  its 
thousands  of  miles'  momentum  on  the  sensitized  plate.  The 
picture,  therefore,  is  already  there;  because  the  impression 
has  been  made.  It  remains,  consequently,  to  find  a  reduc- 
ing agent  so  refined  and  energetic  as  to  effectuate  the  proper 
reduction.  With  the  ordinary  quantity  of  acids  in  our  de- 
velopers, we  can  scarcely  hope  for  success ;  but  with  their 
diminution,  and  a  proportionate  increase  of  velocity  in  the 
manipulation  of  flowing  the  plates,  and  of  stopping  the  fur- 
ther advance  of  reduction,  instantaneous  photography  has,  in 
my  opinion,  to  seek  a  clue  for  its  reliable  performance.  As 
a  general  rule  in  practice,  the  photographer  requires  less  acid 
in  the  developer  according  as  the  time  of  exposure  is  less  ; 
consequently,  the  positive  on  glass,  or  prepared  iron  plate, 
called  the  ambrotype  and  the  melainotype,  requires  a  much 
less  acid  developer  than  the  negative,  where  the  time  of  ex- 
posure is  much,  longer.    In  like  manner,  two  photograpl  lers 


REDUCING  AGENTS — DEVELOPERS. 


103 


may  be  in  the  habit  of  operating,  the  one  with  short  expo- 
sures, and  the  other  with  long  exposures;  but  it  will  be 
found  that  the  developer  of  the  former  is  much  less  acid 
than  that  of  the  latter.  Now  it  may  be  asked  :  What  is  the 
reason  that  the  same  developer  can  not  be  used  for  the  two 
kinds  of  pictures  ?  Because,  in  the  case  of  ambrotypes,  if 
the  developer  be  acid  as  is  the  case  for  negatives,  the  reduc- 
tion will  be  very  slow,  and  most  likely  ineffectual/  whilst  in 
the  case  of  a  negative,  the  non-acidified  developer  would  be 
too  rapid  and  too  unmanageable. 

The  temperature  is  a  very  influential  item  in  modifying 
the  operation  of  development.  The  higher  the  temperature 
the  greater  the  quantity  of  acid  required  to  preserve  the  ex- 
act equilibrium  between  fogging  on  the  one  hand  and  defi- 
ciency of  development  on  the  other. 

The  principal  acids  used  for  this  special  purpose  are  acetic 
acid,  tartaric  acid,  citric  acid,  and  formic  acid.  The  latter 
may  be  regarded  at  the  same  time  a  developer  from  its 
power  of  reducing  metallic  salts,  and  from  its  analogy  to 
acetic  acid  as  a  check  upon  development. 

Acetic  Acid. 

Symbol,  C4  H3  03  HO.    Combining  Proportion,  60.   Specific  Gravity,  1.063. 

Acetic  acid  belongs  to  a  small  group  of  which  acetyle  is 
the  base  or  compound  radical  derivative  from  ethyle  by  the 
oxidation  of  two  equivalents  of  its  hydrogen  in  the  formation 
of  water.  When  alcohol  and  ether  burn  in  the  air  the  pro- 
ducts of  combustion  are  carbonic  acid  and  water.  But  some- 
times the  oxidation  of  the  hydrogen  alone  takes  place,  and 
water  only  is  formed,  together  with  a  small  series  of  new 
bodies  containing  the  same  number  of  equivalents  of  carbon. 
Some  of  the  substances  arise  from  the  decomposition  of  col- 
lodion, such  as  aldehyde,  etc.  This  acid  may  be  formed 
directly  from  the  oxidation  of  alcohol  or  by  substituting  two 
equivalents  of  oxygen  in  the  place  of  two  of  hydrogen. 
Platinum-black  acting  upon  the  vapor  of  alcohol  will  pro- 
duce this  reaction  ;  or  a  small  quantity  of  yeast,  or  almost 
any  other  nitrogenized  organic  material  undergoing  putre- 
factive decomposition,  added  to  dilute  alcohol  and  exposed 
to  the  air  induces  the  same  reaction.  In  this  manner  vinegar 
and  alecar  arise  from  the  slow  acetic  fermentation,  as  it  is 
denominated,  of  weak  wines  and  beer.  When  hard  dry 
wood  or  twigs,  or  oak,  beech,  etc.,  are  submitted  to  destruct- 
ive distillation  at  a  red  heat,  acetic  acid  is  one  of  the  pro- 
ducts of  the  distillate.    The  first  nart  of  the  sour  liquor 


104 


REDUCING  AGENTS — DEVELOPERS. 


which  distills  over  by  a  second  operation  is  not  acetic  acid : 
the  second,  however,  contains  the  acid,  but  is  impure.  It  is 
now  saturated  with  hydrate  of  lime  or  carbonate  of  lime,  by 
which  process  acetate  of  lime  is  formed.  Sulphate  of  soda 
is  then  added  in  solution  to  the  acetate  of  lime  as  long  as 
any  precipitate  of  sulphate  of  lime  falls.  The  resulting  ace- 
tate of  soda  is  filtered  from  the  lime  salt,  and  evaporated  to 
its  crystallizing  point  and  then  set  aside  until  crystals  are 
formed.  The  latter  are  drained  as  much  as  possible  from 
the  water  and  adhering  tarry  liquor,  and  then  heated  cau- 
tiously to  fusion,  by  which  the  tar  is  decomposed  and  ex- 
pelled. The  fused  mass  is  again  dissolved  and  crystallized. 
By  decomposing  this  salt  by  means  of  an  equivalent  of  sul- 
phuric acid  and  by  distillation  we  obtain  strong  acetic  acid, 
which,  by  rectification  over  red  oxide  of  lead,  can  be  con- 
centrated so  as  to  yield  crystals  at  a  low  temperature.  This 
is  denominated  glacial  acetic  acid,  and  melts  into  a  colorless 
liquid  above  60°  Fahr.  It  boils  at  a  temperature  of  240° ; 
its  vapor  is  inflammable.  It  mixes  in  all  proportions  with 
water,  alcohol,  and  ether.  The  acetates  are  very  numerous ; 
all  of  them  are  soluble ;  those  of  silver  and  mercury  the 
least  so. 

Its  photographic  uses  are,  as  above  described,  to  check 
the  vehemence  of  reduction  by  the  developers ;  it  is  used 
also  to  acidify  the  nitrate  of  silver  bath  in  connection  some- 
times with  acetate  of  soda,  and  with  this  connection  it  is 
said  to  yield  much  sensitiveness  and  intensity  with  a  plain 
iodized  collodion. 

Formic  Acid, 

Symbol,  C2  H03  HO.    Combining  Proportion,  46.    Specific  Gravity,  1.235. 

This  acid  is  so  called  because  it  is  found  in  ants,  from  the 
Latin  of  which  the  word  is  derived.  It  bears  the  same  re- 
lation in  the  methyle  group  as  acetic  acid  does  in  the  ethyl e 
series  ;  acetic  acid  being  formed  by  the  substitution  of  two 
equivalents  of  oxygen  for  two  of  hydrogen  in  the  formula 
for  alcohol,  whilst  formic  acid  arises  from  the  substitution 
of  two  equivalents  of  oxygen  for  two  of  hydrogen  in  the 
formula  for  wood-spirit,  a  substance  very  analogous  to  alco- 
hol. This  acid  can  be  obtained  by  distilling  ants  in  water. 
It  is  an  organic  acid,  however,  which  can  be  formed  artifi- 
cially by  heating  organic  substances,  such  as  sugar,  starch, 
etc.,  with  oxidizing  agents.  Thus  :  mix  one  part  of  starch 
or  sugar  or  tartaric  acid  with  four  of  the  binoxide  of  man 
ganese,  four  of  water,  and  four  of  sulphuric  acid.    By  this 


REDUCING  AGENTS  DEVELOPERS. 


10£ 


mixture  carbonic  acid  will  be  liberated  with  effervescence. 
As  soon  as  this  is  over  the  materials  are  subjected  to  distill- 
ation until  four  parts  and  a  half  have  passed  over.  The  acid 
liquor  thus  obtained  is  impure  formic  acid,  which  is  purified 
by  neutralizing  it  with  carbonate  of  soda,  and  evaporating 
the  solution  so  as  to  obtain  formiate  of  soda  in  crystals 
which  may  be  freed  from  all  impurities  in  the  same  manner 
as  acetate  of  soda  in  the  preceding  paragraphs.  From  the 
pure  formiate  of  soda,  any  other  formiate,  or"  formic  acid, 
may  be  obtained  by  neutralizing  the  formiate  with  sulphuric 
acid  and  by  distillation.  Hydrated  formic  acid  is  a  limpid, 
colorless  fluid,  of  an  intensely  pungent  odor;  it  fumes  slight- 
ly ;  at  a  temperature  below  32°  Fahr.  it  crystallizes  in  bril- 
liant plates;  it  boils  at  212°.  It  produces  a  blister  on  the 
skin  when  concentrated.  In  very  many  respects  it  is  very 
similar  to  acetic  acid,  but  may  be  distinguished  from  the 
latter  by  its  comportment  with  oxide  of  silver  or  mercury, 
in  which,  when  heated,  it  reduces  the  metal  after  a  while 
and  liberates  carbonic  acid.  This  acid  is  obtained,  and  per- 
haps most  easily,  by  the  decomposition  of  oxalic  acid  in  con- 
tact with  glycerine  and  by  distillation. 

Photographic  Uses  of  Formic  Acid. 

From  the  similarity  between  acetic  and  formic  acid  it  may 
easily  be  inferred  that  either  might  be  substituted  for  the 
other  in  the  developer,  but  the  reader  will  have  remarked  a 
decided  difference  in  their  action  on  silver  salts ;  and  it  is 
just  on  these  salts  that  the  acid  is  brought  into  action  ;  it  is 
in  fact  an  excellent  reducing  agent,  and  when  heated  is  used 
by  several  distinguished  photographers  in  their  developing 
solutions,  of  which  the  formula  will  be  given  in  the  proper 
place. 

Citric  Acid. 

Symbol,  C12  Ho  0n  +  3  HO  +  2  Aq. 

This  acid  is  obtained  from  the  juice  of  limes,  lemons, 
orange,  currant,  quince,  cranberry,  red  whortleberry,  and 
other  fruits.  The  juice  is  imported  in  the  liquid  state  from 
the  West-Indies,  and  being  in  connection  with  much  mucil- 
age and  other  organic  impurities,  it  is  liable  to  undergo  de- 
composition on  the  way,  and  to  yield  in  the  preparation  of 
citric  acid  other  acids  endowed  with  different  properties 
On  this  account  it  is  advisable  in  many  instances  for  the 
photographer  to  prepare  his  own  citric  acid. 


106 


REDUCING  AGENTS  DEVELOPERS. 


Preparation. 

Take  ten  ounces  of  expressed  lemon-jtiice  ;  boil  the  juice 
for  a  few  minutes,  then  add  to  it  after  it  is  cool  the  whites 
of  three  eggs,  and  stir  the  mixture  so  that  the  albumen  is 
intimately  broken  up  and  mixed  with  the  juice.  Boil  the 
mixture  again,  stirring  it  all  the  while,  and  allow  the  coagu- 
lum  to  settle.  When  cool,  filter  the  sour  liquor  and  boil  it 
again,  adding  to  it  gradually  powdered  chalk  as  long  as 
effervescence  is  produced  ;  citrate  of  lime  is  formed,  which  is 
but  sparingly  soluble  in  water.  The  dark-colored  mucilagi- 
nous liquor  is  filtered  off ;  the  residue  is  well  washed,  and 
afterward  decomposed  by  a  quantity  of  sulphuric  acid  equal 
in  weight  to  the  chalk  employed  in  the  previous  decomposi- 
tion. The  sulphuric  acid  is  diluted  with  about  seven  times 
its  weight  of  water ;  and  the  mixture  is  stirred  about  for 
some  time  until  the  citrate  of  lime  is  completely  decom- 
posed. By  filtration  the  citric  acid  is  separated  from  the 
insoluble  sulphate  of  lime,  and  is  afterward  evaporated 
until  a  pellicle  forms  on  its  surface ;  it  is  then  set  aside  to 
crystallize.  The  dark-colored  crystals  are  removed  from 
the  supernatant  liquid  by  a  strainer  and  again  dissolved  in 
pure  water  ;  the  liquid  is  again  evaporated  as  before,  until 
the  formation  of  a  pellicle  takes  place,  and  is  again  set  aside 
to  crystallize.  By  repeating  the  operation  several  times  the 
crystals  become  quite  clean  and  purified.  Citric  acid  has  an 
agreeably  sour  taste  ;  like  phosphoric  acid  it  is  tribasic,  and 
gives  rise  to  three  classes  of  citrates.  It  is  soluble  in  less 
than  its  own  weight  of  cold  water,  and  in  half  its  weight  of 
boiling  water  ;  it  is  not  very  soluble  in  alcohol. 

Citrate  of  Soda. 
This  salt  is  prepared  by  dissolving  citric  acid  in  pure 
water  and  throwing  into  the  solution,  by  degrees,  pulver- 
ized carbonate  of  soda  as  long  as  effervescence  is  produced. 
The  liquid  is  afterward  evaporated  to  a  crystallizing  consist- 
ency and  then  set  aside.  In  this  case,  as  well  as  in  the  pre- 
ceding, the  mother-liquor  can  be  made  to  yield  new  crops 
of  crystals  by  further  evaporation  or  by  a  repeated  decom- 
position and  a  repetition  of  the  other  proceedings  arising 
out  of  it. 

Photographic  Uses  of  Citric  Acid. 
This  acid  is  frequently  mixed  with  pyrogallic  acid  in  pro- 
per quantity  for  solution  in  water  instead  of  acetic  acid.  It 
is  used  as  a  check  on  the  too  rapid  action  of  pyrogallic  acid, 
and  as  a  reducing  agent.    A  frequent  impurity  in  this  sub 


REDUCING  AGENTS — DEVELOPERS. 


107 


Stance  is  malic  acid,  and  sometimes  aconitic  acid.  Citric 
acid  is  recognized  by  its  producing  in  a  diluted  state  no  im- 
mediate precipitate  with  Chloride  of  Calcium  /  but  an  im- 
mediate precipitate  is  formed  when  the  solution  is  boiled. 

Tartaric  Acid. 

Symbol,  C8  H4  O10+  2  Aq. 

This  acid  exists  in  combination  with  potassa  in  most  kinds 
of  fruit,  and  sometimes  in  a  free  state.  Its  combinations  in 
fruit  are  cream  of  tartar  and  tartrate  of  lime.  The  former 
exists  in  abundance  in  grape-juice,  and  is  denominated,  in 
the  crude  state,  Argol  or  Tartar,  which  is  either  red  or 
white  according  to  the  wine  from  which  it  is  deposited  dur- 
ing fermentation. 

Preparation  of  Tartaric  Acid. 

This  acid  is  obtained  from  argol,  or  from  cream  of  tartar, 
which  is  a  bitartrate  of  potassa,  by  two  processes  ;  one  con- 
sists in  abstracting  one  equivalent  of  tartaric  acid  from  the 
bitartrate,  and  the  other  in  decomposing  the  residual  tar- 
trate in  the  solution.  Following  the  formula  of  the  London 
College,  and  using  the  imperial  gallon,  which  contains  ten 
pounds  of  water,  the  method  stands  thus  :  take  of  bitartrate 
of  potassa  four  pounds ;  boiling  distilled  water,  two  gallons 
and  a  half;  prepared  chalk,  twenty-five  ounces  and  six 
drachms  ;  diluted  sulphuric  acid,  seven  pints  and  seventeen 
fluid  ounces ;  hydrochloric  acid,  twenty-six  fluid  ounces  and 
a  half,  or  as  much  as  may  be  sufficient.  Boil  the  bitartrate 
of  potassa  with  two  gallons  of  the  distilled  water,  and  add, 
by  degrees,  the  half  of  the  chalk  ;  when  the  effervescence  is 
over,  add  the  remainder  of  the  chalk,  previously  dissolved  in 
the  hydrochloric  acid,  diluted  with  four  pints  of  the  distilled 
water.  Then  set  aside  until  the  tartrate  subsides  ;  after 
which  pour  off  the  liquor,  and  wash  the  tartrate  of  lime  fre- 
quently with  distilled  water  as  long  as  it  has  any  taste. 
Next  pour  on  the  diluted  sulphuric  acid,  and  boil  for  a 
quarter  of  an  hour.  Having  filtered  the  liquor  from  the  in- 
soluble sulphate  of  lime,  evaporate  it  by  a  gentle  heat  until 
a  pellicle  is  formed  on  its  surface  ;  then  set  it  aside  to  crys- 
tallize. By  dissolving  the  crystals  in  pure  water,  filtering, 
and  recrystallizing,  and  by  repeating  these  three  operations 
several  times,  pure  tartaric  acid  may  be  obtained. 

Tartaric  acid  is  not  volatile;  when  heated  it  leaves  an 
abundant  coaly  residue.  It  is  soluble  in  half  its  weight  of 
water ;  it  dissolves  also  in  alcohol.    The  salt  itself  under 


108 


REDUCING  AGENTS — DEVELOPERS. 


goes  no  change  when  exposed  to  the  atmosphere ;  but  its 
solution,  when  long  exposed,  absorbs  oxygen  and  forms 
acetic  and  carbonic  acid.  When  boiled  over  an  excess  of 
oxide  of  silver,  the  same  decomposition  is  produced,  and 
metallic  silver  is  liberated.  When  fused  with  potassa  it  is 
decomposed  into  acetic  and  oxalic  acid  ;  whilst  with  bin- 
oxide  of  manganese  and  sulphuric  acid,  it  gives  rise  to  car- 
bonic and  formic  acid.  Concentrated  sulphuric  acid,  when 
heated  with  the  crystals  of  tartaric  acid,  decomposes  it  and 
separates  carbon,  which  renders  the  mixture  black  ;  and  car- 
bonic oxide  is  evolved  at  the  same  time,  which  burns  with  a 
blue  flame. 


CHAPTEE  XV. 


THE  NITRATE  OF  SILVER  BATH. 

Nothing  can  be  easier  to  prepare  than  the  bath  of  nitrate 
of  silver,  and  yet  there  is  no  preparation  in  the  art  of  pho- 
tography which  produces  so  many  difficulties  and  troubles  to 
surmount  as  the  sensitizing  bath  for  the  iodized  or  bromo- 
iodized  collodion  plates.  In  consequence  of  this  it  becomes 
a  difficult  task  to  prescribe  rules  by  which  such  a  bath  can 
be  preserved  sensitive  under  the  troubles  with  which  it  is  so 
frequently  beset.  The  origin  of  these  troubles  may  be  traced 
to  the  materials  introduced  by  the  immersion  of  the  collo- 
dion plates ;  but  these  deteriorating  materials  are  of  such  a 
heterogeneous  nature,  arising  from  the  decomposition  of  the 
pyroxyline,  of  alcohol,  of  ether,  of  the  iodides,  the  bromides, 
their  bases,  and  of  the  elements  combining  with  them,  that 
it  is  as  yet  an  unsolved  problem,  that  of  determining  precise- 
ly the  cause  of  any  given  abnormal  action  in  the  nitrate  bath. 
It  is  true,  as  regards  the  introduction  of  injurious  substances 
into  the  bath,  all  effects  resulting  therefrom  can  be  avoided 
by  using  the  solution  of  nitrate  of  silver  oily  once.  If  this 
salt  were  not  so  expensive,  this  mode  of  avoiding  trouble 
would  be  by  far  the  wisest  and  the  safest.  In  such  a  case 
the  photographer  would  flow  his  plate  with  the  silver  solu- 
tion in  the  same  manner  as  with  the  developing  or  fixing  so- 
lution, using  just  sufficient  to  cover  the  film  and  to  sensitize 
it.  All  the  residual  part  might  be  collected,  decomposed, 
and  fresh  nitrate  prepared.  But  because  the  silver  salt  is  a 
dear  material,  we  aim  to  economize  by  using  the  solution 
over  and  over  again.  For  this  purpose,  glass,  porcelain  or 
photographic-ware  baths  are  constructed  for  containing  the 
fluid.  They  are  made  so  as  to  accommodate  the  largest 
plate  with  the  least  quantity  of  the  solution,  a  great  mistake 
superinduced  by  false  economy.  In  this  country  vertical 
baths  seem  to  be  the  only  ones  employed  ;  whereas  in  France 
and  Germany,  for  economical  and  other  special  reasons  al- 
ready alluded  to,  horizontal  dishes  contain  the  solution,  and 


110 


THE  NITRATE  OF  SILVER  BATH. 


the  plates  lie,  as  it  were,  collodion  side  downward  in  a  thin 
layer  of  the  same.  Some  of  these  baths  are  especially  adapted 
for  the  tourist,  admitting  the  fluid  to  be  closed  hermetically 
by  means  of  India-rubber  caps,  screws  and  clamps.  Nitrate 
of  silver  will  permeate  through  the  parietes  of  porcelain  baths; 
the  photographic -ware  bath  and  the  glass  are  not  subject  to 
this  inconvenience. 

Preparation  of  the  Sensitizing  Solution. 
An  ounce  Avoirdupois  contains  437.5  grains ;  the  druggists 
and  photographic  dealers  retail  all  their  chemicals  accord- 
ing to  this  weight,  and  not,  as  many  suppose,  according  to 
the  Troy  weight,  of  which  the  ounce  contains  480  grains. 
The  sensitizing  solution  is  found  by  experience  to  be  suffi- 
ciently strong  if  it  contain  from  35  to  40  grains  to  the  fluid 
ounce  of  water,  or  from  8  to  10  per  cent. 

Formula  No.  1. 

Nitrate  of  silver,  (recrystallized,)     .    .      3  ounces. 

Distilled  or  pure  rain-water,   36  ounces. 

Washed  iodide  of  silver,  6  grains. 

Washed  oxide  of  silver,  6  grains. 

Dissolve  the  nitrate  of  silver  in  half  the  water,  then  add  to  it 
the  washed  iodide  of  silver,  prepared  as  directed  on  a  preced- 
ing page,  afterward  add  to  the  mixture  the  six  grains  of  ox- 
ide of  silver,  which  is  prepared  as  follows :  Take  a  solution  of 
ten  grains  of  nitrate  of  silver  and  drop  into  it  a  solution  of 
pure  caustic  potash,  as  long  as  a  brown  precipitate  is  formed. 
Then  filter  and  wash  the  brown  oxide  on  the  filter  many 
times  with  cold  water,  and  afterward  with  warm  water,  until 
the  filtrate  ceases  to  have  any  action  on  red  litmus  paper. 

The  mixture  is  now  boiled  in  a  large  glass  flask  on  a  sand- 
bath,  and  when  cold  the  remaining  water  is  added  to  it,  and 
the  whole  of  it  is  filtered  through  a  double  filter  of  Swedish 
filtering  paper.  The  solution  so  prepared  will  be  saturated 
with  iodide  of  silver,  so  that  it  will  not  dissolve  any  of  the 
iodide  of  silver  on  the  collodion  film ;  it  will  be  besides  per- 
fectly neutral,  if  the  oxide  of  silver  has  been  thoroughly 
washed  from  any  adhering  alkali.  With  a  collodion  con- 
taining free  iodine,  either  from  decomposition  or  by  insertion, 
this  bath  is  exceedingly  sensitive,  and  produces  at  the  same 
time  clear  pictures.  For  colorless  collodions  it  is  not  suit- 
able, nor  for  collodions  which  are  quite  freshly  made,  with- 
out the  addition  of  iodine,  that  is,  for  those  which  have  not 
had  time  to  ripen,  as  it  is  termed  in  ordinary  language. 

For  such  collodions,  the  colorless  and  pale  colored  collo= 


THE  NITKATE  OF  SILVER  BATH. 


Ill 


dions,  containing,  as  they  generally  do,  cadmium  salts,  the 
following  bath  will  be  found  to  be  quite  effective  in  produc- 
ing good  results  : 

Formula  No.  2. 

Nitrate  of  silver,  (recrystallized,)     .    .      3  ounces. 

Distilled  or  rain-water,  36  ounces. 

Iodide  of  silver,  (washed,)     ....      6  grains. 

Mix  as  before,  and  filter  without  boiling.  For  each  ounce  of 
nitrate  of  silver  add  one  drop  of  nitric  acid.  This  amount  will 
probably  be  found  sufficient  to  produce  a  clear  picture ;  should 
the  picture  show  any  signs  of  fogging,  add  another  drop,  and 
so  proceed  until  the  details  of  the  development  appear  with- 
out a  universal  cloudiness  over  the  plate. 

Formula  No.  3. 
Nitrate  of  silver,  (recrystallized,)    .    .      3  ounces. 
Distilled,  or  pure  rain-water,    .    .    .    .36  ounces. 
Iodide  of  silver,  (washed,)  .    .    .    .    .      6  grains. 

Prepare  as  before,  and  after  filtration  divide  the  quantity  into 
two  lots  of  18  ounces  each.  Neutralize  one  of  these  with 
washed  oxide  of  silver  by  boiling,  and  then  filter.  Add  to 
the  other  18  drops  of  a  solution  of  acetate  of  soda,  (contain- 
ing 160  grains  to  the  ounce  of  water,)  and  10  drops  of  gla- 
cial acetic  acid.  Each  of  these  baths  may  be  used  separate- 
ly, or  in  mixture.  The  neutral  bath  is  kept  neutral  without 
admixture ;  but  to  the  second,  containing  the  acetate  of  soda 
and  accetic  acid,  a  portion  of  the  first  may  be  added  as*  re- 
quired from  time  to  time,  if  it  is  found  to  work  too  slowly. 
As  a  general  thing  the  acetate  of  soda  bath  produces  very 
vigorous  pictures,  and  renders  the  collodion  film  quite  sensi- 
tive. 

In  summer  the  bath  need  not  be  so  strong  in  nitrate  of  sil- 
ver as  given  in  the  preceding  formulas.  Six  or  seven  grains 
a>f  silver  per  cent  of  the  water  will  be  sufficient  when  the 
temperature  is  high  ;  on  the  contrary,  from  eight  to  ten  per 
cent  may  be  used  when  the  temperature  is  moderate  or  low. 
The  sensitizing  solution  works  quicker  when  warm  than  when 
cold. 

When  the  sensitizing  solution  becomes  weak  by  exhaus- 
tion, it  can  be  restored  to  a  good  working  condition  by  the 
addition  of  a  stronger  solution  of  nitrate  of  silver,  containing 
40  or  50  grains  to  the  ounce  of  water.  After  a  bath  has  been 
in  operation  for  some  time,  it  becomes  saturated  with  a  va- 
riety of  impurities,  such  as  ether,  alcohol,  acetic  acid,  aldehyde, 
the  various  nitrates  in  the  collodion,  and  a  variety  of  sub- 


112 


THE  NITRATE  OF  SILVER  BATH. 


stances  arising  from  the  decomposition  of  this  heterogeneous 
mixture.  The  best  way  to  get  rid  of  all  volatile  material  is 
to  subject  the  solution  to  distillation,  until  all  the  ether  and 
alcohol,  at  least,  have  been  expelled,  and  then  to  filter  the  res- 
idue in  the  retort,  and  to  mix  it  with  a  new  bath.  Although 
such  a  restored  bath  will  give  good  results  for  a  while,  it  soon 
gets  out  of  order,  and  can  no  longer  be  relied  upon.  In  suck 
a  case  it  is  far  more  expedient  to  set  it  aside  for  reduction, 
and  to  form  a  totally  new  bath,  than  to  be  at  the  trouble  of 
a  second  distillation,  because  the  fixed  salts  have  accumulat- 
ed to  such  a  degree  as  to  render  the  bath  very  capricious  and 
unstable. 

When  a  bath  does  not  yield  clear  pictures  when  first  formed, 
or  ceases  to  do  so  after  a  given  time  with  the  same  collodion, 
or  happens  not  to  do  so  with  a  new  collodion,  it  is  advisable 
not  to  trifle  with  the  bath  by  adding  either  acid  or  alkali. 
It  may  be  well  to  ascertain  by  test-paper  whether  the  trouble 
is  attributable  to  alkalinity  or  acidity.  If  no  alkali  has  been 
added  to  the  bath,  it  will  probably  have  an  acid  reaction. 
In  this  case  it  is  preferable  to  boil  the  bath  with  the  washed 
oxide  of  silver,  as  before  prescribed,  and  then  to  filter  it. 
Should  the  bath  turn  out  to  be  neutral  to  test-paper,  it  will 
be  found  in  general  a  better  practice  to  add  a  few  drops  of 
tincture  of  iodine  to  the  collodion,  rather  than  to  acidify  the 
sensitizing  solution  ;  because  the  iodine  in  the  collodion  lib- 
erates an  acid  by  decomposition  on  and  in  the  film  of  collo- 
dion, which  rectifies  the  evil  wThere  the  rectification  is  wanted, 
and  at  the  proper  time,  without  changing  materially  the  con- 
ditions of  the  bath.  Thus  the  operator  will  learn  to  use  up 
a  highly  colored  collodion  by  mixing  it  gradually,  as  it  is 
wanted,  with  new  and  almost  colorless  collodions,  in  order 
to  clarify  his  pictures,  without  resorting  to  methods  of  at- 
taining to  the  same  result  by  adding  acid  to  the  bath. 

During  the  time  the  bath  is  in  use,  a  quantity  of  insoluble 
material  of  a  gray  or  violet-gray  color  is  precipitated  on 
the  bottom  and  sides  of  the  bath,  and  frequently  floats 
about  in  the  sensitizing  fluid.  The  particles  of  this  material, 
as  well  as  of  the  acicular  crystals  of  acetate  of  silver  in  a  weak 
bath  are  apt  to  attach  themselves  to  the  moist  collodion  film 
on  its  immersion,  and  thus  give  rise  to  the  innumerable  small 
apertures  sometimes  exhibited  on  the  developed  negative. 
These  particles  are  not  the  sole  cause  of  this  evil,  so  much 
dreaded  ;  but  they  frequently  cause  it  by  their  attachment  to 
the  film  during  the  exposure,  and  owing  to  their  opacity,  pre- 
vent the  actinic  action  from  taking  effect  on  the  film  be- 


THE  NITEATE  OF  SILVER  BATH. 


113 


neath,  and  becoming  loosened  by  the  developing  and  fixing 
solutions,  afterward  expose  the  transparent  parts  on  which 
they  had  rested.  It  is  advisable,  therefore,  to  expose  the 
bath  in  a  glass  vessel  to  the  rays  of  the  sun  as  often  as  possi- 
ble, in  order  that  the  organic  matter  may  be  precipitated. 
The  bath,  too,  ought  to  be  filtered  very  frequently  in  the 
same  filter,  at  least  once  a  week ;  and  if  every  evening,  so 
much  the  better.  After  filtration  the  bath  can  be  strength- 
ened by  an  addition  of  fresh  solution,  in  proportion  to  the  daily 
work  performed.  See,  during  filtration,  ^hat  the  sides  and 
the  bottom  of  the  vessel  are  perfectly  clean  before  the  solu- 
tion is  poured  back  again.  A  long  thin  wooden  spatula,  with 
a  piece  of  sponge  at  the  end,  will  be  found  very  convenient 
for  clearing  away  the  adhering  gray  deposit.  Use  only  rain- 
water for  rinsing  ;  rinse  thoroughly ;  then  turn  the  bath  wrong 
side  up,  and  rear  it  on  one  corner,  in  order  that  every  drop 
of  water  may  thus  be  removed.  Wipe  the  edges  before  the 
sensitizing  fluid' is  again  introduced.  This  exposure  to  the 
rays  of  the  sun,  and  frequent  filtration  will  remedy  in  a  great 
measure  the  trouble  alluded  to,  and  there  is  no  fear  of  in- 
juring the  property  of  the  solution,  for  nitrate  of  silver  alone 
is  not  acted  upon  by  light,  does  not  change  at  all  when  pure. 

By  exposing  the  solution  in  a  vessel,  such  as  a  glass  eva- 
porating dish,  much  of  the  superfluous  ether  and  alcohol  will 
pass  off  in  vapor,  and  thus  produce  a  remedy  for  another  evil 
which  an  old  bath  invariably  gives  rise  to,  namely,  that  of 
causing  oily-looking  stains  and  streaks  on  the  surface  of  the 
film. 

Where  the  trouble  of  recrystallizing  the  nitrate  of  silver 
would  be  deemed  too  great,  and  neutral  nitrate  of  silver 
can  not  easily  be  purchased,  I  would  recommend  that  the 
photographer  should  fuse  the  nitrate  of  silver  in  a  porcelain 
evaporating  dish,  at  a  gentle  heat,  and  afterward  pour  out  the 
fused  mass  on  a  silver  or  marble  plate,  as  directed  in  the 
manufacture  of  lunar  caustic.  The  same  proportions  of  the 
fused  nitrate  are  used  as  in  the  formulas  for  the  recrystallized 
nitrate.  Or  a  strong  solution  of  the  nitrate  may  be  boiled  with 
the  washed  oxide  of  silver,  filtered,  and  evaporated  to  dry. 
ness,  and  used  in  the  same  way. 


CHAPTER   XV  L 


THE  DEVELOPING  SOLUTIONS. 


In  the  ordinary,  or  wet-collodion  process,  there  are  three 
Developing  Solutions,  the  Protosulphate  of  Iron  Developer, 
the  Pyrogallic  Acid  Developer,  and  the  New  Developer, 
with  the  double  salt  of  the  sulphate  of  the  protoxide  of  iron, 
and  the  sulphate  of  ammonia. 

Sulphate  of  Iron  Developer. 
Formula  No.  1.    For  Ambrotypes  and  Melainotypes. 
Crystals  of  the  protosulphate  of  iron,  .    3  drachms. 


Pulverize  the  iron  salt,  if  it  has  not  been  precipitated  in  al- 
cohol, and  mix  it  intimately  with  the  rain-water  in  the  mor- 
tar ;  then  add  the  acid  and  the  alcohol,  and  see  that  the  so- 
lution is  complete  ;  then  filter  and  use.  From  a  previous  ob- 
servation on  the  subject  of  developing,  it  will  be  conceived 
that  the  quantity  of  acid  must  vary  according  to  several  cir- 
cumstances. In  summer,  that  is,  when  the  temperature  is 
high,  more  acid  will  be  required  to  keep  the  reducing  agent 
in  check ;  in  like  manner,  if  the  time  of  exposure  has  been 
too  long,  the  development  or  decomposition  is  more  easily 
accomplished,  and  on  this  account  more  acid  is  required.  On 
the  contrary,  in  winter,  when  the  temperature  is  low,  as  also 
when  the  time  has  been  very  short,  as  for  example,  for  in- 
stantaneous operations,  the  proportion  of  acid  may  be  dimin- 
ished, until  finally  the  solution  of  the  iron  salt  may  be  used 
without  any  acid.  In  such  cases  it  is  well  to  have  a  bath  of 
the  solution,  into  which  the  exposed  plate  can  be  immersed 
almost  instantaneously,  and  treated  with  the  ordinary  acid 
solution  afterward.  Considerable  dexterity  is  required  in 
this  twofold  operation.  Of  course  diminishing  the  iron  salt, 
or  increasing  the  acid  are  correlative  expressions,  and  signify 
almost  the  same  thing,  the  slight  difference  depending  upon 


Rain-water, 
Acetic  acid, 
Alcohol,  . 


4  ounces. 
3  drachms. 
2  drachms. 


THE  DEVELOPING  SOLUTIONS. 


115 


the  influence  of  the  water  which  remains  stationary,  or  rela- 
tively increases  sometimes  in  favor  of  the  iron,  and  some- 
times of  the  acid. 

Formula  No.  2.    For  Negatives. 

Crystals  of  the  sulphate  of  the  protoxide  of  iron,  .  2  drachms. 

Distilled,  or  rain-water,   32  drachms. 

Acetic  acid,   3  drachms. 

Alcohol,   3  drachms. 

Pulverize  and  mix  as  before.  A  negative  requires  a  longei 
exposure  than  the  ambrotype,  or  the  melainotype ;  the  iron, 
therefore,  is  diminished  whilst  the  other  ingredients  remain 
the  same.  In  the  first  formula  a  drop  or  two  of  pure  nitric 
acid  may  be  added,  because  it  produces  a  more  reguline 
reduction  of  the  silver  salt,  and  leaves  a  very  beautifully 
white  metallic-looking  film  where  the  light  has  acted.  Too 
much  nitric  acid  would  spoil  the  picture  by  producing  too 
intense  a  reduction,  accompanied  with  irregularity  of  depo- 
sition. 

Formula  No.  3.    For  Negatives. 

Pyrogallic  acid,  (pure,)     .    .  ■  .    te  grains.  )    N    x  g  j  . 
Acetic  acid,  2  ounces.  ) 

Shake  the  solution  well,  and  keep  in  a  dark  place. 

Of  No.  1  Solution,    ....     2  drachms.  )    XT  now 
Distilled  water,   14  drachms.  \   Na  2  Solutlon' 

The  reduction  by  this  developer  is  quite  appropriate  for  ne- 
gatives ;  its  color  is  grayish,  but  not  metallic  in  appearance. 
This  developer  is  very  manageable,  and  very  successful.  It 
requires,  however,  a  longer  exposure  than  the  iron  develop- 
er, in  the  ratio  of  three  to  one,  from  my  own  experience  in 
out-door  photography.  It  is  not  so  apt  to  fog  a  picture  as 
the  iron  developer. 

Formula  No.  4.    For  Negatives. 

Pyrogallic  acid,    .    .    24  grains.  )  Divide  into  doaes  of  2  grains. 
Citric  acid,   ....  24  grams.  )  ° 

When  required^  dissolve  a  two-grain  dose  of  the  preceding 
in  four  drachms  of  distilled  water.  The  amount  of  citric 
acid  can  be  modified  according  to  the  same  circumstances 
which  regulate  the  treatment  with  acetic  acid. 

DisderVs  Developer. 

Sulphate  of  the  protoxide  of  iron,    ...  4  drachms. 

Water,   12  ounces. 

Acetic  acid,   4  drachms. 

7 


116 


THE  DEVELOPING  SOLUTIONS. 


Lieut.-  Colonel  Stuart  Worthy's  Developer. 

Sulphate  of  iron,   20  ounces. 

Distilled  water,  120  ounces. 

Dissolve. 

Acetate  of  lead,  ounce. 

Water,  5  ounces. 

Dissolve. 

Mix  the  above  solutions,  and  as  soon  as  the  precipitate  has 
settled,  decant  off  very  carefully.  Add 

Formic  acid,  5  ounces. 

Acetic  ether,  1£  ounces. 

Nitric  ether,   1-J  " 

This  mixture  is  the  stock  solution,  from  which  a  portion  is 
taken,  when  required,  and  filtered  for  use. 

Meynier's  Developer. 

Double  sulphate  of  the  oxide  of  iron  and  ammonia,  .    100  grains. 

"Water,  .    .    23  ounces. 

Acid  acetic,  4  to  8  drachms. 

Alcohol,  4  W 

Or  the  preceding  formula  may  stand  as  follows  : 

Sulphate  of  the  protoxide  of  iron,  69  grains. 

Sulphate  of  ammonia,  3Y  " 

Water,  24  ounces. 

Acetic  acid,  4  to  8  drachms. 

Alcohol,  4  drachms. 

HocJciri's  Developer. 

Formic  acid,  (strong,)  2  drachms. 

Pyrogallic  acid,       .    .   20  grains. 

Distilled  water,   9£  ounces. 

Alcohol,  \  ounce. 

This  developer  is  poured  upon  the  plate,  and  kept  there  un- 
til the  intensity  is  deep  enough.  It  acts  more  quickly  than 
the  pyrogallic  acid  containing  acetic  acid,  but  less  so  than 
the  iron  developer  ;  but  it  is  less  liable  to  fog  than  the  iron 
developer,  and  can  consequently  be  retained  longer  on  the 
plate. 

WaldacJc's  Formulas  for  Collodion  Positives. 

Formula  No.  1.    For  Bead -Whites. 

Sulphate  of  iron,  3  drachms. 

Water,  .  6£  ounces. 

Acetic  acid,  4  drachms. 

Alcohol,  3  drachms. 

Nitrate  of  potassa,   ...  30  grains. 


THE  DEVELOPING  SOLUTIONS.  117 

Formula  No.  2.    For  Brilliant  and  Metallic  Whites. 

Sulphate  of  iron,  85  grains. 

Water,  6J  ounces. 

Acetic  acid,  1  drachm. 

Alcohol,  1£  drachms. 

Nitrate  of  potassa,  30  grains. 

Solution  of  nitrate  of  silver,  30  grains. 

Nitric  acid,  10  drops. 


In  all  the  preceding  formulas,  alcohol  may  or  may  not  be 
added,  according  to  circumstances.  It  is  used  when  the  de- 
veloper does  not  flow  easily  over  the  plate,  forming,  as  it 
were,  oily  streaks  on  the  surface.  It  remains,  therefore,  with 
the  artist  to  use  or  reject  it,  as  it  may  be  found  necessary. 


CHAPTEE  XVII. 


FIXING  SOLUTIONS. 

Fixing  solutions  consist  of  chemical  substances  that  dis- 
solve the  sensitized  salts  of  silver  on  plates  or  paper,  on  which 
photographic  images  have  been  developed.  The  parts  which 
form  the  image  are  covered  with  reduced  silver,  or  an  altered 
iodide  or  chloride  of  silver,  which  is  insoluble  in  the  fixers  ; 
whereas  those  parts  which  have  not  been  impressed  by  the 
actinic  rays  are  made  transparent  with  the  fixing  solutions, 
which  dissolve  the  opaline  silver  compounds,  and  cause  the 
picture  afterward  to  be  unchangeable  when  exposed  to  light. 
The  fixing  solutions  at  present  in  use  are :  Cyanide  of  po- 
tassium, Hyposulphite  of  soda,  and  Sulphocyanide  of  ammo- 
nium. 

Cyanogen. 

Symbol,  C2N,  or  Cy.   Combining  Proportion,  26.   Spec.  grav.  1.819, 

This  substance  is  properly  a  Bicarbide  of  Nitrogen ;  it  is  a 
very  important  material,  as  being  the  type  of  what  are  de- 
nominated compound  salt-radicals ;  it  was  the  first  of  this 
class  of  bodies  discovered.  Cyanogen  is  always  produced  in 
combination  when  an  alkaline  carbonate  is  heated  with  or- 
ganic matter  containing  nitrogen.  It  does  not  exist  either 
in  a  free  or  combined  state  in  nature ;  it  is  a  production  of 
decomposition,  in  which  the  elements  contained  in  it  are 
brought  together  in  the  nascent  state,  in  connection  with 
some  metallic  base. 

Preparation  of  Cyanogen. 
This  compound  radical  is  obtained  by  heating  either  a  cya- 
nide of  silver  or  of  mercury  in  a  flask  of  hard  glass  ;  a  gas, 
the  substance  in  question,  is  produced,  which  may  be  col- 
lected, by  reason  of  its  greater  specific  gravity  than  air,  in 
a  tall  glass  jar,  by  directing  the  outlet  tube  to  the  bottom ; 
or  it  may  be  collected  over  mercury.  It  is  colorless,  but  its 
odor  is  quite  peculiar  and  characteristic.  It  burns  with  a 
peach-colored  flame,  yielding  carbonic  acid  and  nitrogen. 
Water  dissolves  four  volumes  of  this  gas,  and  alcohol  as 
much  as  twenty-five  volumes.    An  aqueous  solution  is  de- 


FIXING  SOLUTIONS. 


119 


composed  when  exposed  to  light  into  a  variety  of  ammonia- 
cal  compounds.  By  the  pressure  of  four  atmospheres  it  i& 
reduced  to  the  liquid  state.  It  combines  with  alkaline  solu- 
tions  precisely  in  the  same  way  as  chlorine,  iodine  and  bro 
mine,  and  gives  rise  to  salts  denominated  cyanides. 

Hydrocyanic  Acid — Prussic  Acid. 
Symbol,  H  Cy. 

This  acid  is  obtained  from  the  cyanides  or  the  ferrocyan- 
les  by  the  superior  affinity  of  the  mineral  acids  for  their 
oases  in  a  manner  similar  to  that  by  which  the  other  hy- 
dracids  are  obtained.  Take,  for  instance,  three  parts  of  the 
yellow  prussiate  of  potash  (ferrocyanide  of  potassium)  in 
fine  powder,  two  parts  of  sulphuric  acid,  and  two  of  water, 
and  distill  the  mixture  in  a  flask  or  retort ;  the  vapor  which 
passes  over  is  condensed  in  a  receiver  surrounded  by  ice. 
Prussic  acid  is  a  colorless  liquid  of  the  specific  gravity  of 
0.6969.    It  is  exceedingly  poisonous. 

Cyanide  of  Potassium. 
Symbol,  K  Cy. 

This  substance,  so  exceedingly  useful  to  the  photographer, 
might  be  formed  by  passing  the  vapor  of  hydrocyanic  acid 
through  a  solution  of  potassa  to  saturation,  and  then  evapo- 
rating to  dryness  without  access  of  air.  It  is  formed,  how- 
ever, by  heating  ferrocyanide  of  potassium  in  an  iron  bottle 
to  an  intense  red  heat ;  the  tube  of  the  bottle  dips  into  water 
to  conduct  away  the  gases.  The  cyanide  of  iron  becomes 
decomposed  into  carbide  of  iron  and  charcoal,  and  its  nitro- 
gen is  given  off,  whilst  the  cyanide  of  potassium  remains  un- 
decomposed,  and  when  melted  swims  on  the  surface  of  the 
porous  black  mass  below.  It  is  afterward  pulverized  and 
dissolved  in  boiling  weak  alcohol,  from  which  it  crystallizes 
as  the  alcohol  cools  ;  or  whilst  in  a  fused  condition  it  is 
poured  upon  marble  slabs  and  afterward  broken  up  and 
bottled.  This  substance  is  almost  as  poisonous  as  hydro- 
cyanic acid,  but  being  a  fixed  salt  it  is  easily  detected  in 
the  stomach ;  whereas  hydrocyanic  acid,  by  reason  of  its 
volatility,  seldom  leaves  any  trace  behind  by  which  the 
cause  of  death  can  be  recognized.  This  salt  is  decomposed 
by  the  red  oxide  of  mercury  into  cyanide  of  mercury  and 
potassa,  showing  the  superior  affinity  of  cyanogen  for  mer- 
cury. On  this  account  the  ordinary  tests  for  mercury  do 
not  act  on  cyanide  of  mercury,  with  the  exception  of  hydro- 
sulphuric  acid  ;  analogous  to  hyposulphite  of  silver  in  which 
hydrochloric  acid  or  a  soluble  chloride  does  not  precipitate 


120 


FIXING  SOLUTIONS. 


the  chloride  of  silver,  hydrosulphuric  acid  alone  being  capa 
bie  of  forming  a  precipitate. 

Sulphocyanide  of  Potassium. 
Symbol,  Cy  S*  K. 

This  salt  is  obtained  by  a  process  similar  to  the  last  with 
an  addition  of  sulphur  to  the  amount  of  half  the  weight  of 
the  ferrocyanide  of  potassium  used.  It  is  an  excellent  test 
of  the  persalts  of  iron,  with  which  it  produces  blood-red  pre- 
cipitates. I  do  not  see  why  this  salt  may  not  be  used  in- 
stead of  the  following  as  a  fixer ;  it  certainly  can  be  more 
easily  procured,  and  is  no  doubt  just  as  poisonous. 

Sulphocyanide  of  Ammonium. 
Symbol,  Cy  S2  NH*. 
This  is  the  new  fixing  salt  of  Meynier  which  is  said  to  be 
endowed  with  properties  for  photographic  purposes  as  pow- 
erful as  those  of  cyanide  of  potassium,  without  having  the 
poisonous  and  otherwise  deleterious  properties  of  this  salt. 
Meynier,  I  think,  must  have  made  a  mistake  as  to  this  latter 
property.  Sulphocyanide  of  ammonium  may  be  formed  by 
distilling  the  vapor  of  hydrocyanic  acid  into  a  solution  of 
sulphide  of  ammonium  and  evaporating  the  solution  at  a 
very  gentle  heat ;  or  still  better  by  neutralizing  hydrosul- 
phocyanic  acid  by  means  of  potassa. 

Hydrosulphocyanic  Acid. 
Symbol,  Cy  S2  H. 

This  acid  is  analogous  with  the  hydracids  ;  it  is  obtained 
as  a  colorless  liquid  by  decomposing  sulphocyanide  of  lead 
by  means  of  dilute  sulphuric  acid ;  and  sulphocyanide  of 
lead  results  from  the  decomposition  of  sulphocyanide  of  po- 
tassium with  acetate  of  lead. 

Hyposulpfdte  of  Soda.  . 
Symbol,  N4  0,  S2  0*. 

This  very  important  salt  is  obtained  by  digesting  sulphur 
in  a  solution  of  sulphite  of  soda,  which  dissolves  a  portion 
of  sulphur.  By  slow  evaporation  the  salt  crystallizes.  Hy- 
posulphurous  acid  can  not  be  isolated  from  any  of  its  com- 
binations. When  this  salt  is  pure  it  produces  no  precipitate 
with  nitrate  of  baryta.  The  crystals  contain  five  equivalents 
of  water,  and  are  soluble  in  a  very  high  degree  in  this  men- 
struum.   Its  taste  is  nauseous  and  bitter. 

The  photographic  properties  of  the  three  salts,  whose  pre- 
parations have  been  just  indicated,  are  to  dissolve  the  chlo- 
ride, iodide,  and  bromide  of  silver  in  their  recently  formed 


FIXING  SOLUTIONS. 


121 


^u,te,  without  acting  as  solvents  on  the  altered  chloride, 
iodide,  and  bromide,  after  decomposition  by  light  and  de- 
velopers. In  all  cases  of  solution  they  form  cyanide,  sulpho- 
cyanide,  or  hyposulphite  of  silver,  which  frequently  enters 
into  combination  with  the  solvent  and  gives  rise  to  a  double 
salt,  as  the  hyposulphite  of  silver  and  the  hyposulphite  of 
soda,  together  with  either  chloride,  bromide,  or  iodide  of 
sodium.  Chloride  and  bromide  of  silver  are  soluble  to  a 
greater  extent  than  iodide  of  silver  in  hyposulphite  of  soda. 
Cyanide  of  potassium  is  not  only  a  solvent  of  the  silver  salts 
above  mentioned,  but  also  a  reducing  agent ;  it  thus  pro- 
duces in  the  ambrotype  and  the  melainotype  a  whiteness  in 
the  silver  film  which  can  not  be  effected  with  hyposulphite 
of  silver.  For  this  reason  it  is  regarded  by  many  photo- 
graphers as  the  fixing  agent  peculiarly  adapted  for  collodion 
positives  by  reflected  light ;  whereas  in  the  negative,  where 
the  whiteness  of  the  silver  film  is  of  little  or  no  consequence, 
hyposulphite  of  soda  is  regarded  as  the  proper  fixer.  Many 
photographers  disregard  these  refined  distinctions,  and  use, 
in  consequence  of  the  superior  solvent  properties  of  cyanide 
of  potassium,  this  substance  as  a  fixing  agent  indifferently 
for  negatives  and  positives.  But  because  cyanide  of  potas- 
sium dissolves  the  silver  salts  so  easily,  it  has  to  be  used  in 
a  dilute  condition,  and  to  be  watched  very  closely,  other- 
wise it  will  dissolve  at  the  same  time  the  fine  parts  of  the 
image.  Another  reason  why  cyanide  of  potassium  is  pre 
ferred  in  all  collodion  operations,  arises  from  the  difficulty 
of  washing  the  hyposulphite  of  soda  and  of  silver  from  the 
collodion  film ;  for  if  any  trace  of  these  salts  be  left,  the  col- 
lodion film  will  eventually  be  destroyed  by  crystallization 
taking  place  on  its  surface,  accompanied  with  a  decoloration 
and  soiling  of  the  image. 

Formula  No.  1. 
Fixing  Solution  with  Cyanide  of  Potassium. 


Cyanide  of  potassium,  1  drachm. 

Rain-water,  4  ounces. 

Formula  No.  2. 

Fixing  Solution  with  Hyposulphite  of  Soda. 

Hyposulphite  of  soda,  2  ounces. 

Water,  4  " 

Formula  No.  3. 
Fixing  Solution  with  Sulphocyanide  of  Ammonium. 

Sulphocyanide  of  ammonium,   1  drachm. 

Water,  12  ounces. 


CHAPTER  XVIII. 


INTENSIFIEKS. 

Intensified  are  substances  which,  when  applied  in  solu- 
tion to  the  developed  image,  increase  the  opacity  of  the 
shadows  and  middle  tints,  rendering  them  more  imperme- 
able to  light  in  direct  positive  printing.  With  a  proper  ad- 
justment of  light  and  developer,  and  especially  in  ordinary 
landscape-photography,  an  intensifier  is  seldom  needed ;  but 
many  artists  prefer  the  use  of  the  intensifier  on  every  occa- 
sion ;  they  maintain  that  a  negative  can  always  be  preserved 
as  clear  and  transparent  in  the  lights  as  a  positive  by  this 
process,  and  yet  the  density  of  the  shadows  may  be  increased 
to  any  extent  without  any  fear  of  fogging.  The  intensifying 
process  becomes,  therefore,  a  fixed  part  in  the  preparation 
of  a  negative.  The  operation  is  partly  physical  and  partly 
chemical ;  physical,  because  whatever  may  have  been  the 
action  of  the  light  on  those  parts  in  which  the  image  is  now 
apparent,  they  seem  still  to  be  endowed  with  properties  of 
attraction  of  an  intensity  in  proportion  to  the  development 
produced,  just  as  they  were  at  the  commencement  of  reduc- 
tion ;  but  the  nitrate  of  silver,  iodide  or  bromide  of  silver, 
having  been  exhausted,  the  application  of  any  developer, 
however  sensitive  or  intense,  could  produce  no  more  opacity 
on  the  shadows  for  want  of  material  to  be  reduced  —  but, 
mark  it  well,  the  physical  condition  is  there  to  institute  this 
reduction  the  moment  material  is  supplied. 

From  my  preceding  remarks  it  is  supposed  that  the  de- 
veloped image  consists  of  reduced  silver,  or  an  altered  salt 
of  silver  very  different  from  any  with  which  we  are  ac- 
quainted ;  there  is  no  more  iodide  or  nitrate  of  silver  ;  these 
have  been  removed  in  the  fixing  and  washing.  Now  in  order 
to  restore  the  partially  developed  image  to  the  chemical  con- 
dition requisite  for  the  recommencement  of  the  development, 
a  solution  of  iodine  in  iodide  of  potassium,  or  a  dilute  solu- 
tion of  tincture  of  iodine,  is  flowed  over  the  plate,  and  kept 
in  motion  over  the  image  in  order  to  preserve  uniformity 


INTENSIFIERS. 


123 


of  action.  The  iodine  thus  coming  in  contact  with  the 
silver  shadows  enters  into  combination  with  this  metal, 
and  forms  a  new  and  thicker  deposit  of  iodide  of  silver 
with  all  the  gradations  of  opacity  of  the  image,  and  not  a 
uniform  film  of  deposit.  The  solution  of  iodine  on  the  col- 
lodion loses  color  all  the  while ;  but  the  collodion  film  as- 
sumes at  first  a  grayish  and  then  a  yellowish-gray  hue. 
Even  at  this  stage  there  is  much  more  opacity  in  the  shadows  of 
the  picture  than  before,  and  the  negative  by  this  proceeding 
may  probably  be  dense  enough;  if  not,  proceed  to  the  second 
stage.  The  first  stage  is  the  depositing  stage ;  the  second, 
the  reducing  or  developing  stage  proper ;  and  yet  this  de- 
posit of  the  first  stage  is  a  chemical  combination  of  iodine 
and  silver  which  is  now  soluble  in  the  fixing  solutions,  and 
before  it  was  not.  By  this  process  of  depositing  and  fixing, 
and  by  regulating  the  quantity  of  the  iodine  solution,  a  nega- 
tive which  is  too  opaque  may  be  rendered  more  transparent 
and  less  dense  ad  libitum.  Osborne  has  availed  himself  of 
this  property  to  clarify  his  negatives  for  the  photolithographic 
process ;  I  would  recommend  it  also  in  the  preparation  of 
clear  and  sharp  negatives  for  obtaining  enlarged  positives 
in  the  solar  camera.  As  soon  as  the  depositing  stage  is 
complete,  and  the  film  has  been  washed,  the  collodion  film 
is  ready  for  the  reception  of  the  next  operation. 

The  second  stage  consists  in  communicating  to  the  iodized 
image  a  minute  quantity  of  nitrate  of  silver,  either  alone  and 
diluted,  or  in  connection  with  the  developer ;  it  is,  in  fact,  a 
mere  repetition  of  the  original  process  of  development ;  the 
surface  of  the  collodion  is  in  the  same  condition  as  at  the 
commencement  when  it  left  the  camera ;  there  are  present 
iodide  of  silver,  nitrate  of  silver,  iodide  of  potassium,  the 
peculiar  and  unknown  physical  attraction  existing  in  the 
formed  image,  where  before  the  image  as  yet  was  unformed, 
and  the  developing  solution  either  of  sulphate  of  iron  or 
pyrogallic  acid.  The  second  stage  is  then  a  system  or  pro- 
cess of  redevelopment.  By  this  operation  the  intensity  may 
be  increased  to  any  extent ;  the  shadows  can  be  made  quite 
opaque  and  utterly  impermeable  to  the  actinic  influence. 
The  intensifying  part  of  the  collodion  process  is  Very  much 
m  the  power  of  the  artist ;  success,  therefore,  a\  ill  depend 
principally  on  the  artistic  condition  of  what  I  denominate 
the  Foundation  Negative.  If  the  foundation  negative,  how- 
ever thin  the  shadows  may  be,  contain  lights,  shades,  and 
middle  tones  in  perfect  detail,  then  the  artist  has  it  in  his 
power  to  raise  these  three  conditions  gradually  and  uni- 


124 


INTENSIFIED. 


formly  higher,  until  the  shadows  become  endowed  with  a 
proper  opacity.  At  the  end  of  this  stage  fixing  solutions 
have  but  li  /tle  effect,  which  seems  to  demonstrate  that  the 
yellowish-gray  iodide  has  been  converted  into  an  insoluble 
metallic  film  or  an  unknown  insoluble  silver  salt.  It  is  not 
necessary  to  use  the  fixing  solution.  AH  that  is  required  is 
to  wash  the  image  well  before  it  is  dried  and  varnished. 

Other  deposits  and  other  metals  may  be  introduced  in  the 
intensifying  operations,  which  will  be  found  described  below. 

From  the  recent  experiments  and  observations  of  Blon- 
quart  Evrard,*  it  appears  that  a  negative  may  be  intensified 
by  a  second  exposure  to  light  before  fixing.  Thus,  suppos- 
ing a  negative  be  developed  as  far  as  it  seems  possible  to 
carry  on  the  reduction,  in  this  condition  let  it  be  exposed 
for  a  short  time  to  diffused  light.  This  physical  force,  it 
is  said,  again  acts  actinically,  but  now  only  upon  the  parts 
which  contain  the  image,  communicating  to  these  new  vigor, 
and  a  fresh  impulse,  which,  on  the  application  of  the  devel- 
oper, again  will  assist  in  the  formation  of  further  reduction. 

As  soon  as  the  image  has  been  fixed,  as  in  the  first  exam- 
ple, it  is  sometimes  flowed  with  a  saturated  solution  of  bi- 
chloride of  mercury,  by  which  probably  the  bichloride  is  re- 
duced to  the  protochloride,  and  the  liberated  chlorine  goes 
over  to  the  silver,  and  forms  chloride  of  silver.  This  appli- 
cation communicates  a  whiteness  to  the  image,  and  thickens 
the  deposit.  When  the  negative  has  been  washed,  it  is  flowed 
with  an  iodizing  solution,  containing  five  per  cent  of  iodide  of 
ammonium  in  water.  In  this  way  the  image  becomes  con- 
verted into  a  double  iodide  of  silver  and  mercury,  which, 
when  washed,  is  treated  with  the  iron  or  pyrogallic  devel- 
oper, containing  a  few  drops  of  nitrate  of  silver,  as  before. 
It  frequently  happens  in  this,  as  in  the  preceding  case,  that 
the  film  at  the  end  of  the  first  stage  is  opaque  enough.  In 
this  case  it  maybe  rendered  black  by  flowing  it  with  ammo- 
nia, hyposulphite  of  soda,  or  cyanide  of  potassium. 

A  third  method  of  strengthening  the  dark  parts  of  a  ne- 
gative takes  advantage  of  the  alkaline  sulphides,  which  con- 
vert the  developed  film  into  a  sulphide.  By  this  operation, 
however,  the  film  as  a  rule  is  not  increased  in  thickness,  its 
color  alone  being  changed,  which  is  frequently  more  agreea- 
ble to  look  at,  and  apparently  more  dense,  because  it  is  black, 
or  bluish-black.  These  alkaline  sulphides  may  be  used  with 
advantage  at  the  end  of  the  first  stage  or  deposit,  in  order 


*  Vide  Humphrey's  Journal.    Vol.  XV.    No.  1. 


INTENSIFIERS. 


125 


to  blacken  this  deposit ;  but  by  this  mode  of  intensifying 
there  is  a  great  liability  to  unequal  action,  to  decomposition 
after  the  negative  is  varnished,  to  contraction  of  the  collo- 
dion film,  and  its  separation  from  the  glass  ;  besides  this,  sul- 
phur seems  to  be  precipitated  sometimes  in  very  irregular 
patches,  giving  a  speckled  appearance  to  the  negative. 

Preparation  of  Bichloride  of  Mercury — Corrosive 
Sublimate. 

Symbol,  Hg.  CI.    Combining  Proportion,  136.9.    Spec,  grav.,  5.4. 

Dissolve  red  oxide  of  mercury  in  hydrochloric  acid;  eva- 
porate and  crystallize  ;  or  sublime  a  mixture  of  equal  weights 
of  sulphate  of  mercury  and  common  salt  in  a  stoneware  re- 
tort by  heating  to  redness  in  a  sand-bath.  The  bichloride, 
being  volatile,  passes  out,  whilst  sulphate  of  soda  remains 
behind  in  the  retort.  This  substance  melts  at  509°,  and 
boils  at  563° ;  it  dissolves  in  twenty  parts  of  cold  water,  in 
two  parts  of  boiling  water,  in  two  and  one  third  of  cold  al- 
cohol, and  in  three  of  cold  ether.  When  hydrosulphuric  acid 
is  passed  through  a  solution  of  this  salt,  a  brownish  preci- 
pitate is  first  formed,  which  eventually  becomes  quite  white. 
This  is  a  chlorosulphide. 

Preparation  of  Sulphide  of  Potassium — Hepar  Sulphuris. 

Symbol,  K  &. 

Fuse  together,  at  a  low  red  heat,  one  part  of  sulphur,  and 
two  of  carbonate  of  potash,  as  long  as  effervescence  takes 
place  ;  then  pour  on  to  a  marble  slab,  and  when  cool,  break 
up  the  mass,  and  keep  it  in  well-closed  bottles.  This  sul- 
phide has  a  liver-brown  appearance.  By  the  addition  of  an 
acid  to  a  solution  of  the  sulphide,  hydrosulphuric  acid  is  lib- 
erated, a  soluble  salt  formed,  and  sulphur  precipitated  of  a 
milk-white  color.  The  alkaline  sulphides  have  the  same  re- 
action on  metallic  salts  as  hydrosulphuric  acid,  forming  pre- 
cipitates of  different  colors,  by  wiiich  frequently  the  metalfl 
can  be  recognized,  as,  for  instance,  antimony,  cadmium,  etc. 

Preparation  of  Sulphide  of  Ammonium. 
Symbol,  NH4S.HS. 
Let  a  current  of  hydrosulphuric  acid  pass  through  concen- 
trated ammonia  to  saturation ;  then  add  an  equal  bulk  of 
ammonia.  This  is  one  of  the  most  important  reagents  in 
chemistry.  Hydrosulphuric  acid  produces  precipitates  in 
metallic  salts,  some  of  which  are  soluble  in  sulphide  of  am- 
monium, and  others  not ;  from  this  fact  we  can  distinguish 


126 


INTENSIFIED. 


one  metal  from  another,  thus  the  sulphide  of  arsenic  is  yel- 
low, and  so  is  that  of  cadmium ;  but  the  former  is  soluble  in 
sulphide  of  ammonium,  the  latter  is  insoluble.  The  alkaline 
sulphides  precipitate  silver  black  from  its  solutions ;  thus 
nitrate  of  silver,  as  a  dye  for  the  hair,  is  turned  of  an  intense 
black,  if  followed  up  with  sulphide  of  ammonium. 


CHAPTER  XIX, 


WET  COLLODION  PROCESS. 

If  the  collodionized  plate,  after  sensitization  in  the  silver 
bath,  is  exposed  whilst  still  moist,  the  process  by  which  the 
image  is  obtained,  is  called  the  Wet  Collodion  process ; 
whereas  if  the  sensitized  plates  are  dried,  and  used  after- 
ward at  any  indefinite  time,  the  process  of  the  operation  is 
denominated  the  Dry  Collodion  process.  The  Wet  Collo- 
dion process  will  form  the  subject  of  the  following  chapters. 
This  process  is  divisible  into  two  branches,  comprehending 
the  methods  of  preparing  collodion  positives  and  collodion 
negatives. 

Collodion  Positives — Tlie  Melainotype — The  Ambrotype. 

A  collodion  positive  may  be  viewed  either  by  reflected 
light  or  transmitted  light;  by  reflected  light,  in  the  same 
manner  as  any  picture  or  engraving  is  beheld,  that  is,  by 
looking  at  it ;  and  by  transmitted  light,  when  the  picture  is 
seen  in  or  on  glass,  by  looking  through  it,  such  as  the  picto- 
rial representation  on  stained  glass,  or  altar-pieces,  etc. 
Collodion  positive  pictures,  or  portraits  on  glass,  when  re* 
garded  by  reflected  light,  are  denominated  ambrotypes. 
Every  part  of  such  a  picture  is  laterally  inverted ;  it  does  not 
therefore  represent  nature  as  it  is.  For  portraits  this  inver- 
sion of  the  left  side  for  the  right  side  is  of  no  gre&t  conse- 
quence, excepting  in  the  representation  of  objects  in  action, 
such  as  a  sportsman  firing  at  a  woodcock,  a  soldier  parry- 
ing off  the  blows  of  an  antagonist,  or  a  lady  sewing,  etc.,  in 
all  which  cases  the  fowling-piece,  the  sword,  and  the  needle 
will  be  exhibited  in  the  left  hand,  or  on  the  left  side.  The 
artist,  therefore,  has  to  rectify  his  model  in  such  a  way  that 
he  holds,  when  posed,  all  these  accessories  in  an  inverted  or- 
der. Landscapes,  houses,  churches,  etc.,  can  not  be  properly 
represented  in  an  ambrotype  directly  photographed  from  the 
objects ;  the  application  of  collodion  positives,  thereftr  e,  is 
limited  to  portraiture. 


128 


WET  COLLODION  PROCESS. 


Ambrotype. 

There  are  several  things  which  the  photographer  must 
possess,  and  several  arrangements  to  be  made  before  he  can 
take  an  ambrotype.  He  must  have  a  glass-house,  or  operat- 
ing room,  of  course,  with  all  its  accoutrements ;  glass,  collo- 
dion, developer,  and  fixer  must  all  be  ready,  and  in  their 
proper  places,  as  already  described ;  the  sensitizing  bath, 
plate-holders,  water-tanks,  etc.,  all  adjusted. 

The  operation  of  taking  a  collodion  positive  on  glass  con- 
sists of  the  following  subdivisions  : 

First.  Preparing  the  glass. 
Second.  Coating  it  with  collodion. 
Third.  Sensitizing  it. 
Fourth.  Exposing  it  in  the  camera. 
Fifth.  Developing  the  picture. 
Sixth.  Fixing  the  image. 

First  Subdivision. — Preparing  the  ' Glass. 
Glass  suitable  for  the  photographer  must  be  free  from 
flaws  on  the  surface  or  in  the  mass,  flat,  and  quite  transpar- 
ent. It  can  be  procured  already  cut  for  the  various  sizes 
required  ;  or  the  photographer  can  cut  it  himself  from  plates 
of  the  proper  quality.  There  is  quite  a  knack  to  cut  with  a 
diamond  ;  the  line  made  by  a  diamond  on  glass  is  like  the  cut 
made  with  a  sharp  razor  on  a  piece  of  soft  wood  ;  it  is  by  no 
means  a  scratch.  A  diamond  is  wedge-shaped,  and  its  edge 
not  a  straight  line,  but  a  curved  line,  something  like  the  edge 
of  a  cook's  chopping-knife  ;  the  edge  first  makes  an  incision, 
and  the  wedge  splits  its  way  as  the  diamond  proceeds.  The 
position  of  the  edge  has  to  be  found  out,  and  the  diamond 
studied,  before  you  can  cut  with  it,  and  not  scratch  with  it. 
If  you  are  determined  to  cut  your  own  glass,  prepare  a  gla- 
zier's board  and  a  ruler  for  this  purpose,  and  mark  off*  with 
marks  the  different-sized  glasses  used  in  the  art,  as  one  ninth, 
one  sixth,  one  fourth,  one  half,  four  fourths,  and  steresocopic, 
etc.,  plates. 

Next  see  that  your  glasses,  so  far  cut,  are  of  a  right  size 
for  your  plate-holders  ;  for  it  is  very  annoying  when  the  film 
is  sensitized  to  find  that  the  plate  is  either  too  big  or  too 
small  for  the  holder.    Never  omit  this  precaution. 

The  next  duty  is  to  take  the  glass  in  the  left  hand,  and 
with  the  right  hand  to  run  a  file  along  each  edge  of  the  cut 
glass,  beginning  at  the  left-hand  corner,  and  proceeding  to 
the  right-hand  corner  all  the  way  round ;  the  glass  is  then 


WET  COLLODION  PROCESS. 


12S 


turned  round  to  the  other  side,  and  its  edges  are  treated  in 
the  same  manner.  The  object  in  view,  by  thus  abrading  the 
edges,  is  firstly  to  take  precautions  against  the  cutting  pro- 
perties of  such  sharp  edges ;  and  secondly,  it  is  found  that 
the  collodion  film  adheres  better  to  the  edges  of  the  glass 
when  it  is  so  prepared. 

If  you  are  provided  with  a  patent  vice,  placed  right  in  front 
of  you  in  an  appropriate  place,  on  the  table  or  bench  in  the 
operating  room,  (and  such  a  vice  is  a  very  useful  accessory,) 
the  plate  is  fixed  in  this  horizontally.  ISTow  take  the  bottle 
containing  prepared  rotten-stone,  covered  at  the  wide-mouthed 
orifice  with  a  piece  of  gauze,  instead  of  being  closed  with  a 
cork,  and  dust  a  small  quantity  of  rotten-stone  upon  the  cen- 
ter of  the  plate  ;  then  drop  upon  the  rotten-stone  on  the  plate 
from  ten  to  twenty  drops  of  alcohol,  and  with  a  piece  of  Canton 
flannel,  rub  the  mixture  about  from  side  to  side,  and  in  the 
center  until  the  surface  of  the  glass  is  perfectly  clean.  A 
clean  piece  of  the  flannel  is  then  used  to  remove  all  the  re- 
maining particles  of  rotten-stone,  after  which  the  plate  of 
glass  is  seized  with  a  silk  handkerchief,  so  that  the  fingers 
do  not  come  in  contact  with  the  glass,  which  is  turned  round, 
clamped,  and  its  surface  is  cleaned  in  like  manner.  Both 
sides  being  now  apparently  clean,  again  seize  the  plate  with 
a  clean  silk  handkerchief  in  the  left  hand,  remove  it  from  the 
vice,  and,  holding  a  clean  silk  cloth  in  the  right  hand,  go 
round  the  edges,  remove  all  dust  from  them,  aud  from 
either  side,  then  breathe  upon  either  side ;  if  the  breath 
forms  a  uniform  film,  and  vanishes  uniformly  without  any 
irregularity,  the  surfaces  are  cleaned.  By  this  system  of 
friction  the  glass  becomes  electrified,  and  small  fibers  of  cot- 
ton or  silk  and  small  particles  of  dust  are  very  apt  to  be  at- 
tracted to  the  surface ;  these  must  be  removed  by  a  flat  sable 
or  camel's  hair  pencil.  The  plate  is  now  ready  for  the  sec- 
ond operation. 

Second  Subdivision. 

Holding  the  plate  horizontally  by  the  smallest  portion 
possible  of  the  left-hand  corner,  between  the  thumb  and  the 
first  finger  of  the  left  hand,  pour  over  its  surface,  beginning 
at  the  right-hand  corner,  a  sufficient  quantity  of  collodion  to 
cover  it ;  when  it  is  supposed  that  there  is  sufficient  collo- 
dion poured  out,  lower  the  nearest  edge  and  the  nearest 
right-hand  corner,  so  that  the  collodion  can,  by  the  inclina- 
tion of  the  plate,  be  made  to  flow  uniformly  over  the  sur- 
face, and  its  superfluous  quantity  can  be  drained  into  the 


130 


WET  COLLODION  PROCESS. 


collodion  bottle.  A  wide-mouthed  bottle  containing  a  couple 
of  ounces  will  be  found  to  be  an  appropriate  shaped  vessel 
to  contain  the  collodion  for  present  use  when  the  pictures 
are  small.  Collodion  is  apt  to  indurate  around  the  orifice 
of  the  bottle  ;  and  if  this  dry  film  is  not  carefully  removed 
every  time,  it  may  cause  trouble  by  flowing  off  in  fragments 
along  with  the  collodion,  and  thus  spoil  the  collodion  film. 
This  trouble  is  obviated  in  a  great  measure  by  the  use  of 
what  are  denominated  "  cometless  vials ;"  they  are  made 
for  this  special  purpose.  If  £he  collodion  is  thick  and  glutin- 
ous, it  will  be  no  easy  matter  to  obtain  a  film  on  the  glass 
free  from  ridges.  In  such  a  case  an  additional  quantity  of 
alcohol  generally  renders  the  collodion  thinner,  less  glutin- 
ous, and  more  structureless.  Supposing  the  film  to  be  even, 
free  from  ridges,  from  wooliness,  and  specks  of  every  kind, 
allow  every  drop  of  the  collodion  to  drain  off,  then  wait  until 
it  has  set,  which  will  be  effected  in  a  very  short  time.  It  is 
very  easy  to  ascertain  by  a  touch  of  the  finger  on  the  right- 
hand  corner,  whether  the  film  is  sufficiently  dry  or  not ;  if  it 
no  longer  yields  beneath  a  slight  touch,  the  plate  is  ready 
for  the  next  step.  By  the  way,  I  may  here  remark,  that  it  is 
by  far  the  most  advisable  plan  for  a  practical  photographer 
not  to  manufacture  his  collodion ;  unless  he  be  in  some  de- 
gree a  chemist,  acquainted  with  the  neatness  and  accuracy 
of  chemical  manipulations,  and  have  plenty  of  leisure  time 
as  an  amateur,  he  can  seldom  succeed  in  preparing  at  all 
times  when  required  a  reliable  specimen  of  collodion ;  and 
to  prepare  small  quantities  of  collodion,  as  well  as  of  any 
other  chemical  compound,  seldom  comports  itself  with  econo- 
my. Beside  this,  there  is  no  necessity  for  such  a  sacrifice  of 
time  and  economy  in  a  country  like  this,  where  collodion  can 
be  purchased  of  so  superior  a  quality  for  all  the  ordinary 
operations  of  the  practical  photographer.  Only  observe  this 
rule,  make  your  purchases  at  first-class  houses  in  large  cities, 
who  make  it  their  sole  business  to  supply  unadulterated  ma- 
terials. 

Third  Subdivision. 

When  the  film  has  indurated  place  it  upon  the  ledge  of 
the  dipper  and  lower  it  in  one  continuous  and  rather  quick 
motion  into  the  sensitizing  bath.  Take  care  that  no  actinic 
rays  get  to  the  bath  during  this  operation.  After  three  or 
four  minutes  raise  the  dipper  a  moment  and  examine  the 
collodionized  plate ;  if  the  film  is  still  bluish,  and  as  if  covered 
with  streaks  or  specks  of  oil,  lower  it  again  and  let  it  remain 


WET  COLLODION  PROCESS. 


133 


antil  the  collodion  has  a  yellowish-white  creamy  appearance, 
and  is  free  from  all  oiliness.  Withdraw  it  from  the  bath, 
seize  the  right-hand  corner  between  the  thumb  and  finger 
of  the  right  hand  ;  allow  the  silver  solution  to  drain  off  thor- 
oughly into  the  bath ;  with  a  piece  of  blotting-paper  remove 
all  specks  of  collodion  from  the  back  of  the  plate,  taking 
care  not  to  disturb  the  collodion  along  the  edges  of  the  plate 
or  on  the  film  side ;  remove  the  last  drop  of  silver  from  the 
lowest  corner,  place  it  in  the  plate-holder,  and  close  the  slide 
and  the  shutter.  Previous  to  this,  the  camera  is  supposed  to 
have  been  fixed  before  the  sitter,  and  the  picture  accurately 
focussed.  It  is  supposed,  moreover,  that  the  surface  of  the 
ground-glass  and  the  collodion  film  are  exactly  at  an  equal 
distance,  when  placed  in  the  groove,  from  the  back  lens. 
As  before  observed,  unless  the  picture  is  correct  on  the 
ground-glass,  free  from  all  haze,  bright,  sharp,  and  the  light 
uniformly  subdued,  it  will  be  very  unlikely  that  the  collo- 
dion picture  will  be  a  successful  one  ;  in  fine,  the  image  on 
the  film  will  never  be  better  than  the  one  on  the  ground- 
glass  where  the  lens  has  been  accurately  adjusted ;  and 
furthermore,  that  if  the  picture  on  the  ground-glass  be  clear, 
sharp,  distinct,  and  agreeably  contrasted  with  light  and 
shade,  you  are  legitimately  authorized  to  expect  a  similar 
favorable  result  on  the  collodion.  Be  careful,  therefore,  in 
bringing  every  part  of  the  model  into  as  accurate  a  focus  as 
possible — be  careful  in  the  management  of  the  light. 

Fourth  Subdivision. 
Place  the  cap  on  the  lens  ;  let  the  eye  of  the  sitter  be  di- 
rected to  a  given  point ;  withdraw  the  ground-glass  slide  ; 
insert  the  plate-holder  ;  raise  or  remove  its  slide  ;  Attention ! 
One,  two,  three,  four,  five,  six  !  (slowly  and  deliberately  pro- 
nounced in  as  many  seconds,  either  aloud  or  in  spirit.)  Cover 
the  lens.  Down  with  the  slide  gently  but  with  firmness. 
Withdraw  the  plate-holder  and  yourself  into  the  dark-room, 
and  shut  the  door.    Now  comes  the 

Fifth  Subdivision. 
Placing  the  plate-holder,  still  containing  the  plate,  in  an 
inclined  position  against  the  wall  in  its  regular  and  proper 
position,  open  the  shutter  and  take  out  the  collodion  plate 
carefully,  so  as  not  to  injure  the  film,  by  inserting  the  nail 
of  the  first  finger  along  the  cavity  on  the  upper  part  of  the 
plate-frame,  and  drawing  forward  the  plate  so  as  to  let  it 
fall  into  the  left  hand ;  the  plate  is  then  seized  by  the  left- 


132 


WET  COLLODION  PROCESS^ 


hand  corner  between  the  thumb  and  the  finger.  In  tnis 
position  the  plate  can  easily  be  covered  with  the  developing 
fluid  in  precisely  the  same  way  as  with  collodion,  only  the 
operation  must  be  much  quicker,  in  order  to  cover  the  sur- 
face without  producing  any  lines  of  stoppage,  which  invaria- 
bly happens  unless  the  plate  be  flowed  all  at  once.  When 
the  plate  is  large,  it  is  preferable  to  take  it  by  the  right-hand 
corner  and  lay  it  in  the  left-hand  corner  of  a  gutta-percha 
dish,  whose  lateral  dimensions  are  about  twice  as  large  as 
those  of  the  plate.  Then,  holding  the  dish  in  the  left  hand, 
incline  the  right  side  downward,  and  pour  into  it  a  quantity 
of  the  developing  fluid.  By  a  quick  motion  the  fluid  can  be 
made  to  cover  the  surface  of  the  plate  in  one  continuous 
flow.  As  soon  as  every  part  is  thus  covered  the  plate  is 
taken  out  with  a  quantity  of  the  solution  upon  it,  and  the 
operation  watched.  By  proceeding  in  this  way  two  diffi- 
culties are  avoided ;  the  first  of  which  consists  in  washing 
away  a  portion  of  the  nitrate  or  iodide  of  silver,  etc.,  on  that 
part  on  which  the  solution  is  allowed  to  fall  if  the  first 
method  be  adopted,  whereby  a  diminution  of  reduction  is 
observable  in  this  part ;  secondly,  you  avoid  the  liability  of 
forming  islands  and  curved  lines  of  demarkation  where  there 
is  the  slightest  stoppage  in  the  flowing  of  the  developer. 
Supposing  the  plate  to  be  covered,  however,  you  then  watch 
proceedings.  If  a  bright  silver-white  film  be  desired,  it  is 
well  to  make  use  of  a  slow  developer,  such  as  is  used  for 
negative  purposes,  containing  in  addition  a  few  drops  of 
nitrate  of  silver,  nitrate  of  potassa,  and  nitric  acid.  Take, 
foi  instance,  the  following,  which  is  found  to  work  well  with 
a  white  background,  giving  a  roundness  of  figure  more  like 
that  of  a  daguerreotype. 

Formula  for  Developer. 


Sulphate  of  iron,   2  drachms. 

Rain-water,   8  ounces. 

Acetic  acid,  2  drachms. 

Alcohol,   1  drachm. 

•  Nitrate  of  potassa,   •£  drachm. 

Nitrate  of  silver  solution,  ...  30  drops. 

Nitric  acid,   12  drops. 


The  image  will  gradually  appear,  and  if  the  time  of  ex- 
posure has  been  right,  you  will  be  able  to  observe  the  three 
grades  of  contrast  in  the  development,  that  is,  dark  parts  or 
shades,  middle  tones,  and  lights.  You  will  see,  moreover, 
whether  the  relative  conditions  of  the  collodion  and  the 
;ilver-bath  are  in  good  working  order,  by  the  mode  in  whicb 


WET  COLLODION  PROCESS. 


133 


the  development  takes  place.  If  the  whole  surface  of  the 
collodion  plate  soon  assumes  a  foggy,  milky,  or  clouded  ap- 
pearance, with  but  faint  contrast  between  the  lights  and 
shades,  (and  knowing  that  the  camera  is  quite  impermeable 
to  light  excepting  through  the  lens,)  you  may  fairly  con- 
clude one  of  two  things,  either  that  the  time  of  exposure 
was  too  long,  or  the  condition  of  the  materials  was  not 
normally  good.  Of  these  difficulties  I  will  speak  shortly. 
By  carefully  watching  the  development  it  is  not  difficult  to 
observe  how  the  shades  increase  in  density,  how,  in  fine,  the 
picture  becomes  more  and  more  developed;  and  particularly 
the  photographer  can  distinguish  the  regular  shading  of  the 
background.  At  last  the  development  arrives  at  its  culmin- 
ating point ;  if  it  were  to  proceed  any  further,  the  back- 
ground and  the  transparent  parts  would  begin  to  be  foggy ; 
the  contrast  diminishes,  and  finally  the  picture  is  spoiled. 
The  rule  is  this  :  the  moment  the  image  is  complete  and  the 
background  has  received  its  first  shade,  pour  off  the  remain- 
ing part  of  the  developer,  and  wash  immediately  and  thor- 
oughly by  allowing  a  small  stream  of  rain-water  to  play  upon 
the  surface  until  every  trace  of  the  iron  is  removed.  Wash 
also  the  posterior  side  of  the  glass  in  like  manner.  We  now 
proceed  to  the  sixth  and  last  operation. 

Sixth  Subdivision. — Fixing  Solution. 
Formula. 

Cyanide  of  potassium,  ....  1  drachm. 
Rain-water,  4  ounces. 

Have  this  solution  ready.  With  the  right  hand  place  the 
collodionized  plate  in  a  gutta-percha  dish  held  in  the  left 
hand,  and  pour  upon  the  developed  image  a  quantity  of  the 
above  solution  in  a  gentle  stream,  until  all  the  white  or  yel- 
low iodide  of  silver  has  been  completely  dissolved,  taking 
care  in  the  mean  while  that  the  fluid  is  kept  moving  back- 
ward and  forward,  so  as  to  preserve  uniformity  of  action. 
After  this  operation  wash  the  plate  again  in  many  waters  on 
both  sides  and  until  all  traces  of  the  cyanide  are  removed. 
Holding  the  positive  now  over  a  piece  of  black  velvet  in 
such  a  position  by  a  window  that  the  impingent  rays  shall 
reach  the  eye,  the  quality  of  the  ambrotype  can  be  deter- 
mined. The  picture  must  be  quite  clear ;  the  shades  dark, 
almost  black ;  the  lights  brilliant  and  white  ;  and  in  every 
respect  the  lines  and  points  must  be  sharply  defined.  If 
there  is  no  regular  gradation  of  light  into  shade,  bat  almost 
one  mass  of  shade,  and  the  picture  is  offensively  black,  the 


34 


WET  COLLODION  PROCESS. 


time  of  exposure  was  too  short  or  the  development  not  car 
ried  on  far  enough ;  but  if  in  this  case  the  development  had 
been  continued  until  the  retrograde  action  had  set  in,  then 
certainly  the  time  was  too  short.  The  remedy  in  such  a  case 
is  quite  natural ;  rub  the  picture  out  and  take  another  with 
a  longer  exposure.  If,  on  the  contrary,  the  picture  is  hazy, 
or  foggy  as  it  is  technically  denominated,  and  the  lights  and 
shades  too  much  blended  or  too  little  distinct  from  each 
other,  and  the  development  was  rapid,  and  a  difficulty  pre- 
sented itself  in  discriminating  when  the  reduction  began  to 
assume  a  retrograde  action,  in  such  a  case  it  may  be  confi- 
dently concluded  that  the  time  of  exposure  was  too  long. 
The  remedy  of  course  is  known.  But  the  defects  just  men- 
tioned might  have  been  caused  by  carrying  on  the  develop- 
ment too  long ;  and  it  would  be  very  proper  to  attribute 
these  defects  to  this  cause,  if  the  development  had  been  slow 
and  carelessly  watched.  But  if  the  haze  and  fogginess  com- 
menced almost  as  soon  as  the  developing  solution  was  poured 
upon  the  surface,  you  would  be  justified  in  ascribing  the 
cause  of  this  veil  over  the  picture  to  an  abnormal  condition 
of  the  silver-bath  or  the  collodion.  This  eyil  indicates,  as  a 
general  thing,  alkalinity  in  either  one  or  the  other,  or  in 
both,  and  can  be  remedied  by  rendering  either  one  or  the 
other  acid.  It  may  be  caused  by  a  new  bath  and  a  new 
neutral  silver  solution. 

Remedy  for  Fogginess. 
If  the  collodion  is  nearly  colorless  and  new,  this  material 
is  probably  the  cause  of  the  want  of  contrast  in  the  picture, 
of  the  feebleness  in  the  development,  and,  it  is  possible,  of 
the  veil  that  covers  the  whole  plate.  Take  some  highly 
colored  old  collodion  and  add  it  to  the  new  in  the  propor- 
tion of  one  drachm  in  ten,  and  try  another  picture ;  or  add 
to  the  collodion  tincture  of  iodine,  that  is,  a  solution  of 
iodine  in  alcohol.  In  either  case,  most  likely,  under  the  cir- 
cumstances, an  improvement  will  be  manifest.  If  the  pic- 
ture is  not  yet  perfectly  clear,  proceed  in  the  same  direction, 
that  is,  add  more  of  the  old  collodion  or  of  the  tincture.  If 
the  bath  is  quite  neutral  or  alkaline,  it  will  be  well  indeed  to 
drop  in  a  minim  or  two  of  nitric  acid.  To  do  this  take  a 
drachm  of  distilled  water  and  drop  into  it  five  minims  of 
nitric  acid.  The  mixture  contains  about  sixty  drops,  of 
which  six  drops  will  contain  about  half  a  drop  of  nitric  acid. 
Begin,  therefore,  and  add  six  drops  of  the  solution  to  the 
bath,  and  keep  doing  so  until  the  picture  is  perfectly  satis* 


"WET  COLLODION  PEOCESS. 


135 


factory.  I  prefer  myself  keeping  the  bath  as  nearly  neutral 
as  possible,  and  to  apply  the  remedial  action  to  the  collodion, 
by  adding  free  iodine  or  old  collodion,  of  which  the  former 
seems  by  decomposition  to  liberate  an  acid  in  and  on  the 
collodion  film  in  proper  quantity,  at  the  right  time,  and  in 
the  proper  place ;  and  the  latter,  that  is,  old  collodion,  effects 
the  same  result,  because  it  has  already  undergone  the  de- 
composition of  the  pyroxyline  that  is  called  ripening,  and 
contains  the  materials  for  producing  intensity  and  for  avoid- 
ing fogginess. 

In  taking  collodion  positives  beginners  are  very  apt  to  de- 
velop the  plate  too  long,  as  well  as  frequently  to  expose  in 
the  camera  too  long.  The  right  time  in  both  instances  can 
be  attained  only  by  practice,  after  having  consulted  the  best 
instructions.  As  soon  as  the  picture  is  distinctly  visible  by 
reflection,  stop  the  development ;  if  it  is  then  faulty,  the  time 
was  either  too  long  or  too  short ;  too  short,  if  the  shades  are 
altogether  too  black,  and  transparent  by  transmitted  light, 
and  vice  versa,  if  the  reverse. 

Supposing  the  picture  to  be  correct  and  satisfactory,  we 
proceed  next  to  the 

Seventh  Operation, 

which  consists  in  drying  the  plate.  The  operation  is  per- 
formed by  means  of  the  large  flame  of  an  alcohol  lamp,  or 
by  the  radiating  heat  from  a  stove.  Holding  the  plate  by 
the  left-hand  corner,  between  the  finger  and  the  thumb  of 
the  left  hand,  first  allow  all  the  water  to  drain  off  at  the 
nearest  right-hand  corner,  by  inclining  the  plate  for  this 
purpose;  then  holding  the  lamp  in  the  right  hand,  move  the 
flame  gently  over  the  back  of  the  plate,  so  as  to  avoid  frac- 
ture, beginning  at  the  top  and  proceeding  from  side  to  side, 
and  gradually  downward,  until  the  film  is  thoroughly  dried. 
A  second  inspection  now,  by  viewing  the  picture,  as  before, 
on  a  dark  background,  and  by  reflected  light,  decides  whether 
the  positive  is  good,  tolerable,  or  indifferent,  because  now 
the  final  colors  of  the  shaded  parts  are  attained.  These 
shaded  parts  are  of  a  bright,  white  silvery  hue,  with  the  de- 
velouer  above  given.  Some  tastes  are  more  gratified  with 
a  more  subdued  contrast  in  which  the  whites  are  more  dead- 
ened. This  can  be  effected  by  making  use  of  a  much  more 
rapid  developer,  and  by  omitting  the  nitrate  of  silver,  and 
the  nitric  acid.  For  this  purpose  the  following  formula  will 
be  found  practicable. 


136 


WET  COLLODION  PROCESS. 


Formula  JVb.  2.    For  Collodion  Positives. 

Sulphate  of  the  protoxide  of  iron,     4  drachms. 

Acetic  acid,  6  drachms. 

Water,  8  ounces. 

Alcohol,  2  ounces. 

Nitrate  of  baryta,  2  drachms. 

Mix  intimately,  and  filter  before  using.  Prepare  fresh 
every  day. 

Eighth  Operation. 

The  next  step  which  the  artist  has  to  take  consists  in  re- 
moving any  particles  that  may  have  settled  upon  the  surface 
of  the  picture,  and  in  coloring  the  cheeks,  hands,  and  dra- 
pery where  required.  Dry  colors  are  used ;  those  of  New- 
man are  regarded  as  the  best.  Very  little  color  will  produce 
an  agreeable  effect.  With  a  fine  sable  or  fitch  pencil,  take 
a  small  portion,  and  rub  it  gently  on  either  cheek,  on  the 
lips,  the  hands,  and  forehead ;  then  brush  off  the  extraneous 
quantity,  or  shade  the  color  off  from  the  center  of  the  cheeks, 
for  instance,  to  the  edges.  On  the  lights  of  the  drapery  the 
requisite  coloring  may  be  laid  on  in  like  manner.  This  op- 
eration of  coloring  is  frequently  performed  on  the  varnished 
surface.  Finally  with  a  large  broad  sable  pencil  remove  all 
loose  coloring  particles,  and  now  the  positive  is  ready  for  the 

Ninth  Operation. 

Whilst  the  plate  is  still  warm,  uniformly  warm  from  the 
drying  operation,  flow  it  with  the  purest  and  most  transpar- 
ent crystal  varnish,  precisely  in  the  same  manner  as  the 
plate  was  covered  with  collodion.  The  operation  must  be 
performed  with  dexterity  and  care ;  with  dexterity  in  order 
to  avoid  all  ridges  caused  by  stoppage,  and  with  care  to 
avoid  loss  of  varnish  by  escaping  to  the  posterior  part  of 
the  plate,  upon  the  fingers,  and  upon  the  sides  of  the  bottle, 
and  the  floor.  The  indurated  varnish  on  the  back  of  the  pos- 
itive may  be  removed  by  a  tuft  of  cotton  wool,  dipped  either 
in  alcohol,  benzole,  or  chloroform,  according  as  the  resins  in 
the  varnish  are  dissolved  in  either  of  these  menstrua.  Do 
not  apply  any  heat  from  a  large  flame  on  the  back  of  the 
plate  before  the  varnish  has  dried,  otherwise  the  ethereal 
fluid  in  which  it  is  dissolved  will  take  fire  in  many  instan- 
ces, and  spoil  the  varnished  surface.  When  the  film  is  some- 
what dry  and  indurated,  and  not  quite  smooth,  heat  may  be 
applied  carefully,  in  order  to  remove  the  unevenness,  or  the 
want  of  brilliancy. 


WET  COLLODION  PROCESS. 


137 


Varnishes  for  Collodion  Pictures. 
Formula  No.  1. 

Copal,  1  ounce. 

Pure  benzole,   15  ounces. 

Dissolve  and  filter  through  Swedish  or  ordinary  filtering 
paper. 

Formula  No.  2. 

White  stick  lac,  3  ounces. 

Picked  sandarac,  3  drachms. 

Alcohol,  spec,  grav.,  .815,  .    .    .    40  ounces. 
Oil  of  bergarnot,  6  drops. 

Dissolve  the  resins  in  the  alcohol  by  means  of  a  water-bath, 
and  filter.  This  varnish  is  immediately  ready  for  use  ;  and, 
like  all  varnishes,  is  the  best  when  new. 

Formula  No.  3.    Crystal  Varnish.    Soft  Copal  Varnish. 
Finely  powdered  Dammar  resin,  .     5  ounces. 
Benzole,  50  ounces. 

Set  aside  in  a  closed  vessel  for  a  week,  shaking  the  mixture 
from  time  to  time  for  a  day  or  two  ;  then  allow  the  insoluble 
gum  to  subside.  Draw  off  the  supernatant  liquid,  which, 
when  clear,  is  ready  for  use.  The  collodion  plate  must  be 
quite  dry  and  cold  when  this  varnish  is  applied,  and  the  lat- 
ter is  allowed  to  dry  spontaneously. 

Formula  No.  4.    Amber  Varnish,  (with  Chloroform.) 
Amber  in  fine  powder,    ....      3  ounces. 
Chloroform,  50  ounces. 

Shake  the  mixture  from  time  to  time  for  eight  or  ten  days, 
and  then  filter.  This  varnish,  like  the  preceding,  is  poured, 
like  collodion,  upon  the  cold  plate,  but  with  great  dexterity, 
because  it  dries  very  rapidly. 

Formula  No.  5.    Amber  Varnish,  (with  Benzole.) 

Amber,  3  ounces. 

Benzole,   50  ounces. 

Heat  the  amber  first  in  a  .close  vessel  to  a  temperature  of 
about  570°  Fahr.,  when  it  begins  to  soften  and  swell,  yielding 
white  fumes.  It  is  then  dissolved  in  the  benzole.  This  var- 
nish too  is  flowed  upon  the  cold  plate,  and  allowed  to  dry 
spontaneously.  These  two  varnishes  are  more  especially 
adapted  for  negatives. 

If  it  should  happen  that  a  collodion  picture  becomes  some- 
what spoiled  by  the  cracking  of  the  varnish,  it  is  recommend- 
ed, if  its  restoration  or  preservation  be  of  great  importance, 
to  take  the  following  method.    First  ascertain  whether  the 


138 


WET  COLLODION  PROCESS. 


solvent  of  the  varnish  on  the  plate  be  alcohol,  chloroform,  or 
benzole,  by  dropping  on  one  corner  a  minute  drop  of  each  of 
these  menstrua,  to  ascertain  which  dissolves  the  varnish. 
Next  take  a  tin  box,  somewhat  larger  than  the  picture,  about 
one  inch  deep.  At  the  bottom  of  this  box  solder  a  ring  of 
tin,  about  half  an  inch  wide,  of  the  same  shape,  and  nearly 
of  the  same  size,  as  a  support  for  the  glass  plate.  Pour  a 
small  quantity  of  the  solvent  on  the  outside  of  the  support ; 
place  the  plate  collodion-side  upward  on  the  ring;  cover 
the  box  as  nearly  air-tight  as  possible  with  a  piece  of  glass, 
and  place  it  in  a  water  bath.  The  vapor  of  the  solvent  will 
soon  cause  the  varnish  to  swell,  and  the  edges  of  the  cracks 
to  coalesce.  As  soon  as  this  end  in  view  is  accomplished,  the 
plate  is  carefully  withdrawn,  and,  when  cool,  is  again  var- 
nished with  a  similar  varnish. 

The  plate  having  been  varnished  with  a  transparent  resin 
varnish,  we  proceed  finally  to  the  last  operation. 

Tenth  Operation. 
We  have  now  to  make  a  background  for  the  positive,  of 
some  black  material,  which  may  consist  of  a  piece  of  black 
velvet,  black  paper,  etc.,  of  the  same  size  as  the  plate ;  or  we 
may  apply  a  coating  of  black  varnish,  either  to  the  collodion 
surface,  or  to  the  posterior  surface  of  the  glass.  If  the  var- 
nish on  the  background  be  applied  to  the  collodion  side,  the 
picture  is  not  laterally  inverted,  but  it  loses  considerably  in 
transparency  by  the  intervening  collodion ;  in  consequence 
of  this  inconvenience,  the  background  is  generally  placed  on 
the  side  of  the  glass  without  the  collodion. 

Formula  JSFo.  1.    For  Black  Varnish. 

Oil  of  turpentine,  50  ounces. 

Asphaltum,   2  ounces. 

Canada  balsam,  4  ounces. 

Formula  N~o.  2.    For  Black  Varnish. 
Benzole  or  coal-tar  naphtha,    .    .    50  ounces. 

Asphaltum,  2  ounces. 

India-rubber,   -J-  drachm. 

Formula  No.  3.    For  Black  Varnish. 

Camphene,  50  ounces. 

Pulverized  bitumen,  10  ounces. 

White  wax,  2  ounces. 

Lampblack,  1  ounce. 

Mix  these  ingredients  together,  and  dissolve  by  a  gentle 
heat ;  afterward  filter  and  preserve  in  a  well-corked  bottle. 


WET  COLLODION  PROCESS. 


139 


Varnish  with  bleached  Shell-lac. 


Formula. 

Freshly  bleached  shell-lac,    ...    4  ounces. 

Alcohol,  1  quart. 

Camphor,  2  drachms. 

Canada  balsam,  2  drachms. 


Dissolve  at  a  warm  temperature ;  allow  to  settle,  and  decant 
the  clear  portion  for  use. 

For  muli. 

The  following  varnish  is  used  on  the  cold  plate,  is  very 
hard  when  dry,  and  is  not  softened  at  a  high  temperature 
when  printing. 

Gum  sandarac,  4  ounces. 

Oil  of  lavender,  3  ounces. 

Alcohol,   .    .28  ounces. 

Chloroform,  .    .5  drachms. 

Digest,  dissolve,  and  decant  as  usual. 

The  positive  print,  denominated  an  ambrotype,  is  now  fin- 
ished. It  remains  only  to  fix  it  in  a  case  or  frame.  In  the 
first  place  a  piece  of  very  transparent  and  unblemished  glass, 
of  the  same  size  as  the  type,  is  thoroughly  cleaned,  and  its 
edges  filed,  as  for  collodion  purposes,  and  all  particles  are 
brushed  from  its  surface.  It  is  then  placed  in  a  Preserver  ; 
over  this  comes  a  Mat ;  next  the  Ambrotype.  The  two  lat- 
ter are  then  firmly  folded  within  the  flexible  edges  of  the 
preserver,  and  the  compact  mass  is  finally  adjusted  in  its  ap- 
propriate case. 
8 


CHAPTER  XX. 


ALABASTRINE  POSITIVES. 

The  coloring  of  collodion  positives,  as  already  remarked, 
may  be  effected  on  the  whites  of  the  picture,  either  before 
the  varnish  is  flowed  on,  or  upon  the  varnish  itself.  When  well 
performed,  it  communicates  life  and  roundness  to  a  picture 
which  before  was  flat  and  lifeless.  The  colors  in  use  are  in 
line  powder,  and  are  laid  on  with  a  dry  and  very  fine  pencil 
of  camel's,  etc.,  hair.  Naturally  the  operation  must  be  very 
simple,  and  but  a  very  small  quantity  of  color  must  be  used, 
otherwise  the  operation  will  become  a  work  of  art,  and  none 
but  an  artist  could  perform  it.  In  all  ordinary  cases  the 
color  lies  on  the  surface,  and  does  not  penetrate  into  the  ma- 
terial of  the  film.  In  the  Alabastrine  process,  however,  the 
film  is  so  treated  as  to  become  permeable  to  varnish,  and  thus 
to  exhibit  the  color,  as  it  were,  in  the  collodion ;  besides  this 
the  whites  are  still  retained  white,  notwithstanding  the  im- 
pregnation of  the  film  with  the  penetrating  varnish.  Posi- 
tives treated  in  this  manner  are  regarded  through  the  glass 
and  the  collodion  film ;  the  pictures,  therefore,  are  direct  as 
they  ought  to  be.  The  mode  by  which  the  tones  are  pre- 
served soft  and  white,  and  rendered  at  the  same  time  per- 
meable, is  the  following : 

Alabastrine  Solution. 
Formula. 

Sulphate  of  the  protoxide  of  iron,  .    20  grains. 

Bichloride  of  mercury,  40  grains. 

Chloride  of  sodium,  (salt,)  ...  15  grains. 
Rain-water,  2  ounces. 

Select  for  this  operation  a  vigorous  good  positive  ;  a  faint 
and  thin  film  does  not  answer  well.  One  that  has  been  ra- 
ther under-exposed  is  most  suitable.  Then,  whilst  the  collo- 
dion film  is  still  moist  from  fixing,  pour  upon  it  a  quantity 
of  the  above  solution,  and  keep  it  in  motion.  At  first  the 
picture  assumes  a  dead  and  gray  appearance ;  but  this  soon 
changes,  and  becomes  continually  more  and  more  brilliant. 


ALABASTRINE  POSITIVES. 


141 


It  is  sometimes  necessary  to  add  a  little  more  of  the  fresh 
solution,  and  to  retain  this  solution  on  the  surface  until  the 
whites  are  perfectly  clear.  The  time  required  for  this  oper- 
ation varies  according  to  the  temperature  and  the  thickness 
of  the  film.  Heat  promotes  the  effect ;  the  plate  is  therefore 
frequently  supported  on  the  ring  of  a  retort-stand,  with  the 
fluid  on  its  surface,  whilst  a  small  flame  is  kept  in  motion 
beneath  it.  Unless  this  precaution  be  observed,  there  will 
be  a  liability  to  break  the  plate.  It  happens  sometimes  that 
a  few  minutes  are  sufficient ;  but  generally  more  time  is  re- 
quired. If  no  heat  is  applied,  the  operation  may  require  in 
some  cases  as  much  as  an  hour.  As  soon  as  the  whites  have 
attained  their  utmost  purity,  the  operation  is  complete.  It 
is  better  to  be  quite  certain  that  the  whites  have  attained  the 
purity  required,  than  to  shorten  the  time,  and  have  the  ef- 
fect underdone.  There  is  no  danger  in  giving  too  much 
time ;  but  it  is  a  disadvantage  to  remove  the  fluid  from  the 
plate  too  soon ;  because  in  drying,  the  whites  in  such  a  case 
are  apt  to  grow  darker  again,  and  the  picture  assumes  then 
the  cold  blue  tone,  which  arises  from  treatment  with  corro- 
sive sublimate  alone. 

As  soon  as  the  effect  has  been  reached,  the  plate  is  tho- 
roughly washed  in  several  waters,  and  then  dried  over  the 
spirit-lamp.  The  plate  is  now  ready  for  the  first  coating  of 
varnish,  which  communicates  transparency  to  the  shadows, 
without  at  all  impairing  the  whites. 

The  next  operation  is  to  lay  on  the  colors  carefully  and  ar- 
tistically on  those  parts  that  require  them.  It  is  unnecessary 
to  apply  any  to  the  shades.  Where  much  color  is  desired  on 
a  given  surface,  it  is  better  to  apply  it  by  repetition,  and  not 
in  one  thick  blotch.  Colors  thus  tastefully  laid  on  produce 
a  very  brilliant  effect,  by  reason  of  the  purity  of  the  whites  ; 
and  this  effect  is  again  increased  by  the  softness  communi- 
cated to  the  whole  picture  by  the  application  of  the  penetrative 
varnish,  which  causes  the  color  to  permeate  into  the  pores  of 
the  film,  or  to  be  seen  at  least  in  full  beauty  from  the  oppo- 
site side.  This  varnish  is  nothing  more  than  a  very  pure 
strong-bodied  protective  varnish.  The  picture  so  far  finish- 
ed is  backed  up  with  a  piece  of  black  velvet,  but  never  with 
black  Japan,  which  would  injure  the  film. 


CHAPTER  XXI. 


MELAINOTYPE  EERR  OTYPE . 

The  melainotype  takes  its  name  from  the  black  background 
upon  which  it  is  taken.  Ferrotype  from  the  iron  of  which 
it  is  composed.  Very  thin  plates  of  sheet-iron  are  covered 
with  a  protective  varnish  or  Japan,  of  which  one  is  of  a  rich 
black  or  brown-black  color,  highly  polished,  and  without 
flaw,  for  the  reception  of  the  collodion  and  the  collodion  pic- 
ture. Glass  in  this  sort  of  picture  is  entirely  dispensed  with, 
and  so  is  also  the  black  Japan,  the  black  velvet,  and  paper. 
This  type  is  by  far  the  easiest  and  the  quickest  to  take,  and 
in  general  the  most  satisfactory  when  taken.  Melainotype 
plates  of  all  the  variable  photographic  sizes,  and  of  variable 
qualities,  can  be  obtained  from  the  photographic  warehouses. 
The  Excelsior  plate  and  the  Eureka  plate  in  my  opinion  are 
the  best ;  the  Ferrotype  is  very  good,  and  much  cheaper. 

Operation. 

With  a  fine  flat  sable  pencil  dust  off  any  particles  from  the 
black  surface  of  the  plate,  and  then  flow  it  with  collodion  in 
the  same  way  in  which  the  ambrotype  glass  was  covered. 
Wait  for  the  congelation,  or  partial  desiccation  of  the  film, 
and  then  immerse  it  in  the  silver  until  it  assumes  a  creamy 
opacity,  (not  blue,)  and  until  the  solution  flows  off  without 
apparent  oily  streaks.  Then  raise  it  from  the  bath  ;  allow 
the  superfluous  fluid  to  drain  off  into  the  bath,  and  with  bib- 
ulous paper  remove  the  last  drop  from  the  pendent  corner  of 
the  plate.  The  plate  is  next  inserted  in  its  holder,  and  a 
piece  ol  the  same  size  placed  over  it.  Previous  to  this  part 
of  the  operation,  the  photographer  must  never  forget  to  clean 
out  the  lower  corner  of  the  plate-holder,  by  means  of  blotting 
paper  or  old  rag.  Nitrate  of  silver  is  apt  to  settle  in  these 
corners  ;  and  these  being  formed  of  separate  pieces  of  glass,  ce- 
mented together,  and  not  of  one  solid  mass,  (which  is  Lewis 
and  Holt's  patent,)  the  nitrate  of  silver  becomes  frequently  de- 
composed by  the  material  of  the  cement,  and  running  up  the 
plate  on  the  collodion  side  by  capillary  attraction,  it  pro- 


MELAINOTYPE  FERROTYPE. 


143 


duces  dark-colored  stains  and  streaks.  Make  it  your  duty, 
therefore,  a  part  of  the  collodion  operation  in  fine,  to  clean 
these  corners  carefully  before  you  take  out  the  plate  from 
the  silver  bath. 

The  time  of  exposure  of  a  melainotype  is  the  same  exactly 
as  for  an  ambrotype.  All  the  instructions,  too,  for  develop- 
ing, fixing,  coloring,  and  varnishing  the  positive  on  glass 
are  valid  here.  I  regard  it  as  preferable  to  color  after  the 
plates  are  varnished,  both  in  this  as  well  as  in  the  preceding 
type.  Owing  to  the  better  conducting  qualities  of  heat  in 
iron  plates  over  those  of  glass,  more  caution  is  required  lest 
the  Japanned  film  becomes  raised  into  blisters.  This  misfor- 
tune is  very  common  with  beginners  on  certain  plates,  with 
the  Excelsior,  perhaps,  less  frequently  than  with  some  others. 

This  type  is  mounted  with  glass,  mat,  and  preserver,  and 
fixed  in  a  case  like  an  ambrotype ;  or  it  may  simply  be  covered 
with  a  mat,  and  thus  prepared  for  mailing  in  a  letter.  For 
this  purpose  each  corner  is  cut  olf  with  a  pair  of  shears,  at 
a  distance  of  one  quarter  of  an  inch  from  the  apex,  and  the  cor- 
responding corners  of  the  mat  are  folded  or  reduplicated  over 
and  under  it,  so  as  to  form  a  compact  piece  out  of  the  two. 
The  melainotype,  as  thus  taken  directly  from  the  model,  is  an 
inverted  picture,  like  the  ambrotype,  but,  unlike  the  anibro- 
toype,  it  can  never  by  a  single  operation  be  otherwise.  In 
the  alabastrine  process  just  described,  the  ambrotype,  it  will 
be  observed,  is  not  an  inverted  picture ;  the  plate  is  inverted, 
and  the  image  is  beheld  through  the  collodion  in  its  natural 
and  direct  position. 


i 


CHAPTER  XXIL 


COLLODION  NEGATIVES. 

A  collodion  negative  is  an  actinic  impression,  in  which  the 
different  parts  of  the  image  are,  as  in  the  positives  just  de- 
scribed, laterally  inverted,  and,  when  viewed  by  transmitted 
light,  the  shades  are  where  the  lights  ought  to  be,  and  vice 
versd.  It  is  the  matrix  from  which  positives  are  obtained 
by  direct  contact,  either  on  glass,  or  on  paper,  as  also  by 
means  of  the  lens  in  the  ordinary,  or  in  the  solar  camera. 
Most  of  the  details  of  the  operation  in  the  negative  process 
are  the  same  precisely  as  in  the  positive  process. 

The  glass  is  filed,  cleaned  and  flowed  with  collodion,  as  be- 
fore directed.  It  is  sensitized  too  in  the  same  bath,  and  then  ex- 
posed. Let  the  time  of  exposure  be  from  ten  to  twenty  sec- 
onds in  the  glass-room,  probably  more  ;  much  depends  upon 
the  proper  adjustment  of  the  light,  and  its  concentration  by 
the  lenses.  The  object  in  view  is  to  obtain  much  more  ac- 
tinic action,  not  only  on  the  film,  but  through  the  film,  so  as 
to  produce  a  denser  metallic  reduction  for  the  shades,  which 
in  the  ambrotype  are  lights.  To  guard  against  the  liability 
to  fogging,  a  much  weaker  and  more  acid  developer  is  used 
than  in  the  positive  process.  The  developing  is  carried  on 
as  long  as  the  shades  increase  in  density  by  transmitted  light. 
It  is  quite  an  advantage  in  this  process  to  have  a  small  square 
.of  orange-colored  glass  situated  lower  down  than  the  posi- 
tion of  the  negative,  as  you  hold  it  for  the  operation  of  de- 
velopment, in  order  that  the  light  may  come  from  below,  and 
thus  through  the  glass.  If  fogging  sets  in,  or  the  density 
seems  to  be  stationary,  or  even  to  retrograde,  the  negative 
is  developed  as  far  as  circumstances  in  the  present  instance 
will  permit.  If  the  density  of  the  shades  is  so  great  as  to 
prevent  you  from  distinguishing  objects  through  them,  and 
these  shades  are  regularly  tempered  down  through  the  inter- 
mediate tones  to  the  bright  lights,  and  these  lights  are  still 
clear  and  transparent,  it  is  very  possible  that  the  image  is  suf- 
ficiently negative,  and  that  you  have  succeeded  in  your  under- 
taking. It  is  absolutely  necessary  that  you  should  know  what 


COLLODION  NEGATIVES. 


145 


you  have  to  do,  before  you  can  depend  upon  what  you  do, 
or  rely  on  definite  results.  A  true  negative  is  just  what  I 
have  described.  If  the  lights  are  not  clear  and  transparent, 
with  sufficient  detail,  of  course,  intermingled ;  if  the  shades 
are  transparent,  and  not  comparatively  opaque,  so  much  so 
as  to  allow  the  print  of  a  book  to  be  read  through  them ;  or 
if  there  are  no  intermediate  tints,  but  your  negative  is  all 
black  and  white ;  then  you  have  not  succeeded — your  nega- 
tive is  faulty.  We  will  suppose,  however,  that  the  three 
gradations  of  shades,  middle  tones,  and  lights  exist,  but 
that  the  intensity  of  the  shades  is  not  strong  enough ;  there 
is  a  general  weakness  in  the  negative,  and  your  object  is  to 
push  on  the  development,  which  is  found  to  be  ineffectual 
without  producing  a  haziness  or  fogginess  over  the  whole 
print ;  the  conclusion  to  be  drawn  from  this  circumstance  is 
that  the  time  of  exposure  was  too  short.  Another  sitting 
may  remedy  the  evil.  On  the  contrary,  if  when  the  deve- 
loper is  poured  on,  the  reduction  on  the  shades  is  very  ra- 
pid, and  this  reduction  commences,  rushes  with  rapidity  into 
the  lights  before  you  have  time  almost  to  stop  it,  you  may 
fairly  conclude  that  the  time  was  too  long.  But  a  develop- 
er sometimes  may  produce  very  much  the  same  effect ;  for, 
if  the  proportion  of  the  iron  salt,  in  comparison  with  the 
acid  and  the  water,  be  great,  fogging  and  rapid  reduction 
will  certainly  be  the  result.  As  before  remarked,  a  much 
weaker  developer  is  required  in  the  preparation  of  a  nega- 
tive than  in  that  of  a  positive,  and  a  proportionately  larger 
quantity  of  acid  to  check  its  action,  until  the  proper  density 
of  opacity  is  attained  in  the  shades.  (I  use  the  words  shades 
and  lights  in  the  negative,  to  represent  what  they  really  are, 
and  not  what  they  produce  on  the  paper  print ;  shades  arc 
dark  and  opaque  ;  lights  are  thin  and  transparent.) 

We  do  not  aim  to  obtain  brilliant  white  silver  reductions 
on  the  negative ;  for  the  color,  or  metallic  brilliancy  is  altoge- 
ther a  matter  of  little  consequence ;  on  this  account  we  use 
no  silver  solution  in  our  negative  developer.  Where  the 
time  of  exposure  is  not  necessarily  required  to  be  very  short, 
a  pyrogallic  acid  developer  produces  a  very  pleasing  nega- 
tive. 

Negative  Developers. 

Formula  No.  1.    Iron  Developer. 

Sulphate  of  the  protoxide  of  iron,     4  drachms. 

Rain-water,  8  ounces. 

Acetic  acid,  .  1^  ounces. 

Alcohol,   .6  drachms. 


146 


COLLODION  NEGATIVES. 


Formula  No.  2.    Pyrogallic  Acid  Developer. 

Pyrogallic  acid,  3  grains. 

Water,   2  ounces. 

Acetic  acid,  2  drachms. 

Alcohol,  6  drops. 

The  negatives  which  produce  the  softest  prints  are  those 
which  are  produced  by  the  first  development,  where  the 
time  of  exposure  and  the  action  of  the  reducing  agents  have 
been  in  such  relatively  due  proportion  as  to  produce  the 
three  gradations  with  a  proper  amount  of  opacity  in  the 
shades.  This  proportion  can  not  always  be  determined  be- 
forehand, because  of  the  variability  of  the  light,  and  its  ac- 
tinic powers,  of  which  we  know  as  yet  absolutely  so  little. 
We  can  not  determine  the  reason  of  the  widely  diverse  ac- 
tion of  light  at  six  in  the  morning,  and  six  in  the  evening,  or 
at  the  vernal  equinox,  and  the  autumnal.  In  consequence  ot 
this  want  of  definite  knowledge  of  the  prime  cause  that  in- 
stitutes the  actino-physical  changes  in  the  iodo-sensitized  col- 
lodion film,  it  will  frequently  happen  that  the  developed 
image  is  not  perfect ;  the  shades  are  not  endowed  with  suf- 
ficient opacity.  Fortunately  in  such  cases  we  possess  means 
whereby  these  shades,  middle  tones,  and  detail  in  the  lights 
can  all  be  in  relative  proportion  rendered  more  opaque,  and 
as  much  more  opaque  as  may  be  desired.  The  process  by 
which  this  end  is  attained,  is  denominated  the  Intensifying 
or  Redeveloping  process. 

The  image  having  been  developed  as  far  as  possible  in  ac- 
cordance with  the  rules  laid  down,  the  plate  is  thoroughly 
and  carefully  washed  on  both  sides,  and  freed  entirely  from 
every  trace  of  nitrate  or  developer.  Cyanide  of  potassium 
in  solution,  the  formula  of  which  is  given  at  the  end  of  the 
positive  process,  may  be  employed  to  remove  the  undecom- 
posed  iodides  or  bromides,  care  being  taken  not  to  continue 
the  action  of  the  solvent  too  long,  nor  to  apply  it  in  too  con- 
centrated a  condition,  lest  the  fine  markings  of  detail  are  dis- 
solved off  at  the  same  time.  Because,  as  already  mentioned, 
cyanide  of  potassium  is  a  reducing  agent,  as  well  as  a  fixing 
substance,  and  giving  a  silver  salt  so  acted  upon  a  reguline 
appearance,  it  is  regarded  as  the  fixing  agent  proper  for 
collodion  positives ;  whereas,  owing  to  the  properties  pos- 
sessed by  hyposulphite  of  soda  as  a  fixer  alone,  and  not  a 
reducer,  and  because  its  solvent  action  is  not  so  violent  as 
that  of  the  cyanide,  it  is  properly  recommended  to  fix  nega- 
tive pictures. 


COLLODION  NEGATIVES. 


147 


Fixing  Solutions  for  Negatives. 
Formula  No.  1. 


Hyposulphite  of  soda,  ....  5  ounces. 
Water,   10  ounces. 

Formula  No.  2. 
Cyanide  of  potassium,      ....    1  drachm. 
Water,  .    .  5  ounces. 


In  case  the  image  is  fixed  with  the  first  formula,  that  is, 
with  hyposulphite  of  soda,  the  plate  requires  to  be  washed 
with  the  utmost  care,  for  if  any  of  the  hyposulphite  of  silver 
is  left  in  the  film,  it  will  become  manifest  after  the  drying 
of  the  film,  sometimes  at  the  expiration  of  months,  by  the 
formation  of  a  crop  of  crystals  on  the  surface  that  complete- 
ly ruins  the  picture.  As  soon  as  washed,  the  plate  is  ready 
for  operations  quite  distinct  from  those  in  the  positive  pro- 
cess. 

Intensifying  or  Redeveloping  Process. 

Formula  No.  1.    Depositing  Fluid. 

Iodine,  1  grain. 

Iodide  of  potassium,  1  grain. 

Rain-water,  1  ounce. 

Formula  No.  2.    For  the  Stock  Bottle  of  the  same  material. 

Iodide  of  potassium,  1  drachm. 

Water,  2  ounces. 

Iodine  to  saturation. 

Depositing  Operation. 
Take  from  ten  to  twenty  drops  of  this  solution  to  each 
ounce  of  water,  and  flow  the  developed  plate  with  it.  This 
operation  can  be  performed  in  the  diffused  light  of  day.  The 
plate  must  be  kept  in  motion  all  the  while,  and  the  fluid 
poured  off  and  on,  in  order  to  obviate  all  irregular  deposi- 
tion. The  solution  will  gradually  lose  color,  whilst  the  film 
in  the  mean  time  assumes  a  gray  or  yellowish-gray  hue.  If 
the  negative  does  not  require  much  additional  opacity  in  the 
shadows,  it  is  not  necessary  to  carry  on  the  depositing  oper- 
tion  further  than  the  gray  film.  The  plate  is  now  washed 
again. 

Intensifying  Operation. 

Formula  No.  1.    Nitrate  of  Silver. 

Nitrate  of  silver,  30  grains. 

Rain,  or  distilled  water,     ....    1  ounce. 

Take  three  drops  of  this  solution  with  two  drachms  of 
water,  and  cover  the  plate  with  the  fluid.  Pour  the  fluid  off 
and  on  several  times. 


148 


COLLODION  NEGATIVES. 


Formula  No.  2.    Pyrogallic  Acid.  (Stock) 

Pyrogallic  acid,  .    .    12  grains.    )    ^      .      ,   ,  , 
Acetic  acid,.    .    .    .    1  ounce.     [    Keep  in  a  dark  place 

Formula  No.  3. 

Of  this  take,  1  drachm.  ) 

Water,  7  drachms.  >    For  immediate  use. 

Alcohol,     .    .    .    .10  drops.  ) 

To  two  drachms  of  No.  3,  add  ten  drops  of  No.  1 ;  mix  iiiti* 
niately  by  shaking,  and  then  pour  it  upon  the  plate,  and  keep 
it  in  agitation.  The  shades  will  soon  increase  in  blackness 
and  opacity.  The  operation  is  carried  on  to  the  greatest  ad- 
vantage by  holding  the  negative  over  a  light  reflected  from 
below,  as  in  the  dark-room,  or  near  a  doorway  receiving  its 
light  from  the  sky.  Stand  sufficiently  far  back,  and  side- 
wise  of  the  door,  so  that  the  light  does  not  shine  upon  the 
negative  directly  from  the  sky,  but  is  received  as  it  is  re- 
flected upward  from  the  floor,  etc.,  below.  The  shadows 
will  grow  darker  and  darker ;  and  the  process  has  to  be  stop- 
ped as  soon  as  the  opacity  is  sufficiently  dense.  Experience 
alone  can  tell  you  exactly  when  to  stop.  The  denser  the 
background  in  the  negative,  if  a  white  screen  were  used,  the 
whiter  the  print  will  be ;  but  the  opacity  may  be  so  great  as 
to  require  an  hour  or  two  for  the  subsequent  printing  opera- 
tion, which  is  very  inconveniently  long.  A  certain  connec- 
tion exists,  therefore,  between  the  negative  effect  and  the 
positive  printing  effect  afterward,  which  experience  has  to 
teach ;  and  even  if  you  do  not  execute  your  own  printing, 
this  connection  must  not  be  lost  sight  of.  In  parts  that  must 
really  appear  white  in  the  paper,  the  opacity  must  be  dense 
enough  to  prevent  you  from  reading  print  through  them ; 
taking  this  for  your  guide,  separate  such  a  part  in  the  pic- 
ture ;  keep  your  eye  steadfastly  upon  it  as  it  increases  in 
darkness,  and  when  it  has  arrived  at  the  point  indicated, 
pour  off  the  intensifying  solution,  and  wash  very  thoroughly. 
It  sometimes  happens  that  the  film  becomes  contracted  by 
this  operation,  or  that  the  fluid  gets  between  the  glass  and 
the  film,  and  thus  the  latter  becomes  loosened,  and  is  liable 
to  peel  off.  Careful  experience  will  teach  you  how  to  retain 
the  collodion  in  its  place. 

Where  many  prints  have  to  be  taken  from  a  negative,  it 
is  quite  requisite  to  varnish  the  film  when  dry.  But  almost 
all  varnishes  have  a  penetrating  effect,  like  oil  of  turpentine 
on  paper,  and  thus  diminish  the  opacity  of  the  negative. 
This  has  to  be  taken  into  consideration,  and  the  negative 


COLLODION  NEGATIVES. 


149 


must  be  intensified  in  accordance  deeper  than  required  when 
without  varnish.  The  property  of  a  varnish,  suitable  for 
such  purposes,  must  be  a  sufficient  hardness  of  film  to  pre- 
vent scratches,  insolubility  by  the  heat  of  the  sun,  freedom 
from  any  liability  to  cracking  by  contractility,  perfect  trans- 
parency, as  little  penetrating  power  as  possible,  and  freedom 
from  all  action  upon  the  film. 

Varnish.  Formula. 

White  lac,  4  ounces. 

Picked  sandarac,  4  drachms. 

Alcohol,  (concentrated,)  ....  60  ounces. 

Oil  of  bergamot,  20  drops. 

Dissolve  by  the  aid  of  a  water-bath,  and  filter. 

To  obviate  the  diminution  of  opacity  by  means  of  the  var 
nish,  I  frequently  flow  the  plate  with  a  dilute  solution  of 
gum-arabic  or  gelatine,  which  is  allowed  to  dry ;  and  then 
the  plate  is  varnished. 


CHAPTER  XXIII. 


TRANSFER  PROCESS  OF  COLLODION  POSITIVES  ON  JAPANNED 
LEATHER,  LINEN,  PAPER,  ETC. 

Before  the  preparation  of  the  iron  plates,  known  as  Me- 
lainotype etc.,  the  transfer  process  had  more  importance.  A 
transferred  positive  has  all  the  beauty  of  a  melainotype,  with 
the  advantage  of  being  non-inverted,  and  upon  a  medium 
that  suffers  less  from  being  bent.  It  is  especially  suitable 
for  inclosure  in  letters  to  distant  friends.  Any  fine  sub- 
stance, as  very  thin  leather,  linen,  paper,  etc.,  neatly  and 
evenly  varnished  with  black  Japan,  is  adapted  for  the  recep- 
tion of  the  collodion  transfer.  Such  substances  can  be  ob- 
tained from  the  wholesale  dealers  in  photographic  goods ; 
they  can  also  be  prepared  in  the  following  manner :  Take, 
for  instance,  a  piece  of  fine  leather,  or  oiled  silk,  and  fix  it 
on  a  stretcher,  or  flat  board ;  then  varnish  it  on  one  side  with 
the  following  mixture. 

Black  Japan. 

Chloroform,   .  8  ounces. 

Asphaltum,  8  ounces. 

Canada  balsam,  2  ounces. 

The  ingredients  when  intimately  mixed  are  poured  in  suffi- 
cient quantity  upon  the  side  to  be  japanned,  and  allowed  to 
dry  at  a  gentle  heat.  The  varnish  will  soon  set,  and  in  a  short 
time  will  be  ready  for  the  transfer  operation.  If  metallic 
plates  have  to  be  japanned,  such  as  the  melainotype,  that 
have  to  be  introduced  into  the  silver  bath,  they  must  pre- 
viously be  coated  with  common  positive  or  negative  var- 
nish, in  order  to  be  prevented  from  exercising  any  injurious 
effect  upon  the  silver  bath,  and  afterward  they  are  japanned 
on  one  side,  as  just  described.  These  plates  are  not  used  in 
the  transfer  process,  but  to  receive  the  image  instead  of  glass. 

The  collodion  on  glass,  when  dry,  or  after  it  has  been 
dried,  adheres  to  the  plate  with  considerable  tenacity.  The 
film  for  transferring,  too,  must  be  of  the  glutinous  kind,  con- 
taining more  ether  than  alcohol.    After  the  image  has  been 


TRANSFER  PROCESS  OP  COLLODION  POSITIVES.  151 


fixed,  and  washed,  and  whilst  the  film  is  still  moist,  it  is 
flowed  with  the  following  solution : 

Alcohol,  5  drachms. 

Water,  5  drachms. 

Nitric  acid,  ....  from  12  to  16  drops. 

The  solution  is  immediately  poured  off,  and  the  plate  drained 
of  its  superfluous  fluid.  The  prepared  leather,  etc.,  is  now 
cautiously  laid  upon  the  film,  beginning  in  the  middle,  and 
allowing  either  end  to  fall  gradually  upon  the  collodion,  so 
as  to  exclude  all  bubbles  of  air.  .  The  leather  is  next  pressed 
with  a  burnishing  tool  all  over  the  posterior  surface,  so  as 
to  bring  it  in  intimate  contact  with  the  film  beneath.  If  the 
operation  be  performed  with  dexterity  and  care,  bubbles  of 
air  may  be  avoided ;  if  any  are  observed,  they  must  be  re- 
moved by  drawing  up  the  leather  gently  before  adherence 
takes  place,  and  then  by  letting  it  down  again  with  more 
caution.  Having  succeeded  in  bringing  the  collodion  film 
and  the  leather  in  juxtaposition,  without  a  single  bubble,  the 
plate  is  warmed  gently  over  an  alcohol-lamp,  after  which  the 
leather  can  be  removed,  together  with  the  collodion  film  ad- 
hering to  it.  The  leather  is  now  rinsed  in  pure  water,  and 
allowed  to  dry. 

If  it  be  desired  that  the  collodion  picture  shall  be  in  the 
form  of  an  oval,  circle,  or  square,  etc.,  we  proceed  as  follows  : 
Place  a  mat  with  the  proper  opening  upon  the  collodion  pic- 
ture, and  with  a  pointed  style  go  round  the  picture,  cutting  it  as 
it  were  from  the  glass.  All  the  collodion  on  the  outside  of 
this  line  is  next  removed  with  a  piece  of  wood,  as  for  instance, 
the  end  of  a  match  cut  to  a  flattened  point,  and  made  moist. 
By  using  this  like  a  scraper,  and  keeping  it  moist,  the  collo- 
dion will  gradually  disappear,  and  the  surface  will  be  kept 
clean.  The  picture  is  afterward  transferred  to  leather,  en- 
amelled cloth,  etc.,  by  the  method  just  described. 

Transfer  Paper. 
Paper  is  prepared  as  follows  for  receiving  the  collodion 


positive.  Dissolve 

Asphaltum,   3  ounces  in 

Turpentine,   6  ounces. 

Boiled  oil,   8  ounces. 

Afterward  take — 

India-rubber,  (belting,)    ....  1  ounce. 

Camphene,   2  ounces. 


Dissolve  the  latter  by  a  gentle  heat,  and  then  add  it  to  the 
first  solution.    Shake  the  solutions  well  together,  and  then 


152         TRANSFER  PROCESS  OF  COLLODION  POSITIVES. 


allow  the  mixture  to  settle  for  a  few  days.  It  is  afterward 
decanted  into  a  dish.  Ordinary  unruled  fine  paper,  in  pieces 
of  the  proper  size,  is  floated  on  this  bath,  and  afterward 
hung  up  to  dry.  By  repeating  the  process,  the  paper  finally 
receives  a  very  smooth  surface.  It  will  keep  for  any  length 
of  time.  With  a  mixture  of  one  ounce  of  alcohol,  and  three 
drops  of  nitric  acid,  moisten  both  the  collodion  film  and  the 
prepared  paper  surface,  and  pour  the  surplus  back  again  into 
the  bottle.  Dip  the  plate  and  the  paper  into  soft  water  sev- 
eral times ;  then,  laying  the  plate  on  the  table,  place  the  pa- 
per upon  the  collodion  positive  in  the  manner  already  pre- 
scribed, in  order  to  exclude  bubbles ;  press  them  close  to- 
gether until  the  paper  is  quite  smooth.  The  latter  may  now 
be  raised,  and  removed  from  the  glass,  and  dried. 


CHAPTER  XXIV. 


COLLODION  POSITIVES  ON  GLASS  BY  TRANSMITTED  LIGHT. 

Transparetit  Positives, 

This  kind  of  picture  is  used  more  especially  for  stereosco- 
pic slides.  Its  application  to  church- windows,  etc.,  for  which 
it  is  so  well  adapted,  has  not  yet  been  introduced  to  any  great 
extent.  A  transparent  positive  may  be  produced  either  by 
means  of  the  camera,  or  by  direct  contact  of  the  negative. 
By  means  of  the  camera  the  proceeding  is  as  follows  : 

In  the  first  place  we  require  a  good  orthoscopic  lens,  or, 
in  fact,  any  lens  that  will  produce  with  an  inserted  diaphragm 
a  clear,  well-defined  picture  of  a  page  of  print,  without  dis- 
tortion of  the  marginal  lines.  Ascertain  the  length  of  the  equal 
conjugate  focus  of  the  lens,  that  is,  half  the  distance  between 
the  object  and  its  image,  when  these  are  of  the  same  size. 
Then  construct  a  square  cylinder  of  thin  wood,  in  which  the 
camera  can  slide ;  let  the  inside  be  blackened  with  a  solution 
of  ink,  laid  on  twice.  At  the  end  in  front  of  the  lens,  cut 
out  an  aperture  of  the  size  of  the  negative,  leaving  a  ledge 
of  three  sixteenths  of  an  inch  all  round  on  which  the  nega- 
tive can  rest.  Fix  the  negative  by  means  of  a  tack  or  small 
pin  in  each  corner.  It  is  inverted  laterally,  that  is,  the 
sides  have  changed  places,  left  being  right,  and  right  left ; 
and  the  collodion  side  is  inwards,  or  facing  the  lens.  This 
compound  camera  is  now  pointed  either  to  a  white  cloud,  or 
directly  to  the  sun.  Focus  the  image  on  the  ground  glass 
with  great  accuracy  ;  it  is  much  more  difficult  to  obtain  the 
right  focus  in  such  work  than  in  ordinary  portraiture,  and  a 
microscope  is  invariably  required  to  obtain  a  sharp  and  cor- 
rect copy.  It  facilitates  the  operation  of  focussing  to  find 
some  small  point,  or  mark,  or  wrinkle,  and  then  to  slide  the 
camera  in  the  cylinder  backward  and  forward,  until  you 
think  you  have  got  the  sharpest  definition,  and  afterward  to 
make  the  final  adjustment  with  the  microscope.  Inasmuch 
as  the  lens  is  within  the  cylinder,  all  the  focussing  has  to  be 
performed  by  means  of  the  sliding  of  the  camera ;  and  when 


154       COLLODION  POSITIVES  BY  TRANSMITTED  LIGHT. 

once  the  right  focus  has  been  found,  the  cylinder  and  the  cam- 
era are  firmly  fastened ;  and  a  mark  is  made  by  which  at 
any  time  afterward  the  adjustment  can  be  quickly  made, 
without  resorting  to  an  independent  system  of  focussing  on 
each  occasion  when  a  transparent  positive  has  to  be  taken. 

With  the  bright  rays  of  the  sun,  and  an  orthoscopic  lens, 
probably  as  much  as  from  one  to  three  minutes'  exposure  will 
be  required  ;  whereas,  with  an  ordinary  well-corrected  por- 
trait lens,  the  time  will  vary  from  a  quarter  of  a  minute  up- 
ward. It  is  supposed,  of  course,  that  a  small  stop  is  used, 
so  as  to  obtain  a  sharp  and  undistorted  picture.  With  a 
large  diaphragm,  naturally  a  much  shorter  exposure  would 
be  quite  sufficient.  All  the  rest  of  the  operation  of  eollo- 
dionizing,  developing,  and  fixing  is  the  same  as  that  already 
described.  The  picture  is  developed  near  the  pane  of  glass 
which  admits  light  from  below.  A  bright,  transparent  pic- 
ture is  particularly  required  in  this  operation ;  there  must 
be  no  fogging,  and  the  shades  must  be  pretty  deep  and  dis- 
tinct. 

Such  is  a  general  outline  of  producing  transparent  posi- 
tives on  glass,  by  means  of  the  lens  and  camera  ;  but  there 
are  specialties  that  demand  our  attention.  One  of  these  re- 
fers in  particular  to  the  nature  of  the  negative.  A  bright, 
transparent,  and  clear  negative,  somewhat  less  opaque  in  the 
shado  ws  than  for  the  common  printing  process  on  paper,  is  best 
adapted  for  the  purpose  in  question.  If  a  negative  had  to 
be  specially  prepared  for  producing  transparent  positives,  I 
would  recommend  its  preparation  as  above  described,  only 
giving  a  trifling  less  exposure,  and  using  a  slightly  stronger 
developer.  The  reduction,  too,  must  be  stopped  the  very 
moment  there  is  the  slightest  tendency  to  veiling.  Finally 
after  the  negative  is  fixed,  supposing  it  to  be  already  suffi- 
ciently intense  not  to  require  any  redevelopment,  (which 
is  a  very  desirable  condition,)  it  is  flowed  with  a  solution  of 
iodine  in  iodide  of  potassium  for  a  few  moments,  taking  care 
to  keep  the  fluid  in  motion ;  this  operation  must  be  very  short 
in  duration.  Pour  off*  the  solution ;  wash,  and  again  fix  with 
cyanide  of  potassium.  This  operation  may  be  appropriately 
termed  the  Clarifying  Operation,  for  the  negative  becomes 
quite  clear  and  transparent,  from  the  fact  that  in  those  parts 
where  there  was  a  tendency  to  a  veil  or  fog,  the  reduced  sil- 
ver that  produced  it  has  been  converted  into  iodide  of  silver, 
and  dissolved  by  the  cyanide  in  the  second  fixing.  This 
clarifying  operation  must  be  employed  with  extreme  care, 
lest  the  minute  details  might  be  carried  off  at  the  same  time. 


COLLODION  POSITIVES  BY  TRANSMITTED  LIGHT.  155 


Varnishing,  it  is  true,  will  also  reduce  the  amount  of  density 
in  the  shadows,  but  it  does  not  remove  any  of  the  fogging, 
and  besides  this  it  increases  the  opacity  of  the  transparent 
parts ;  in  short,  it  tends  to  diminish  contrast.  On  this  ac 
count  it  is  preferable  not  to  varnish  the  negative. 

By  fixing  the  negative  in  the  holder  with  the  collodion 
side  next  to  the  lens,  the  positive  collodion  picture  will  be 
on  the  right  side  of  the  glass,  erect  and  free  from  lateral  in- 
version. If  it  were  fixed  otherwise,  then  the  positive  would 
be  on  the  under  side  of  the  glass,  and  would  not  appear  so 
brilliant  when  mounted. 

Another  specialty  to  be  observed,  refers  to  the  color  of 
the  positive.  The  shadows,  after  reduction  with  the  proto- 
sulphate  of  iron,  are  grayish  or  silver-white.  For  viewing 
by  reflected  light,  if  they  were  in  their  proper  place,  they 
would  be  endowed  with  a  very  pleasing  aspect ;  but  viewed 
by  transmitted  light,  the  contrast  is  by  no  means  agreeable  ; 
the  shades  are  too  gray.  The  object,  therefore,  is  to  com- 
municate to  them  a  rich  black  hue.  We  effect  this  by  pour- 
ing over  the  film  a  sufficient  quantity  of  a  saturated  solution 
of  bichloride  of  mercury  free  from  acidity.  As  soon  as  the 
film  is  black,  pour  off  the  mercury,  and  wash  the  plate -in 
rain-water. 

The  next  operation  is  to  flow  over  the  plate  a  saturated 
solution  of  cyanide  of  silver  in  cyanide  of  potassium. 

Formula  No.  1. 
Cyanide  of  potassium,     .    .    .    .    100  grains. 
Kain-water,  2  ounces. 

Nitrate  of  silver  solution,  (50  grains  to  the  ounce,)  as  it>ng 
as  the  precipitate  is  dissolved. 

This  solution,  after  filtration,  is  ready  for  use.  Or  a  solu- 
tion of  cyanide  of  copper  may  be  substituted  for  the  silver 
salt. 

Formula  No.  2. 
Cyanide  of  potassium,    .    .    .    .    100  grains. 
Rain-water,    2  ounces. 

Nitrate  of  copper  solution  as  long  as  the  precipitate  is  dis- 
solved by  shaking.    Filter  as  before,  and  use. 

The  image  when  flowed  with  either  of  these  menstrua  as- 
sumes an  intense  black  hue.  The  solutions  can  be  used  over 
and  over  again  until  exhausted. 

The  plates  are  now  washed  carefully  and  thoroughly,  and 
again  fixed  with  solution  of  hyposulphite  of  soda,  but  not 
with  cyanide  of  potassium,  because  it  reduces  the  silver  tc 


156       COLLODION  POSITIVES  BY  TRANSMITTED  LIGHT. 

a  white  film  again.  This  mode  of  blackening  the  silver  film 
may  be  used  also  as  an  intensifier. 

When  this  operation  is  complete,  the  plate  is  washed  and 
dried,  also  varnished,  unless  the  slide  has  to  be  mounted  with 
a  glass  before  it,  when  the  varnishing  may  be  omitted.  Pre- 
vious to  mounting,  it  may  be  colored  either  on  the  picture 
side  or  on  the  back,  by  which  a  very  rich  effect  is  produced. 
When  positives  are  thus  colored,  they  are  mounted  with  a 
plate  of  ground  glass  behind  them,  and  thin  transparent  glass 
in  front. 

For  the  magic  lantern,  the  slides  must  be  preserved  as 
transparent  as  possible ;  consequently  no  ground  glass  is 
used  behind.  The  coloring,  too,  must  be  laid  on,  either  be- 
fore varnishing,  or  afterward,  very  lightly  and  artistically 
so  as  to  impede  the  passage  of  the  light  as  little  as  possible 


CHAPTER  XXV. 


ENLARGEMENT  OF   NEGATIVES    BY  THE  ORDINARY  CAMERA. 

Having  obtained  a  sharp  transparent  positive,  it  is  evident 
that,  by  a  reverse  process,  a  negative  may  be  reproduced, 
and  of  course  as  many  negatives  as  may  be  required.  It  is 
thus  that  photographic  negatives  may  be  stereotyped.  Not 
only  can  we  thus  procure  a  matrix  for  the  reproduction  of  a 
valued  negative,  (a  proviso  which  ought  never  to  be  omit- 
ted,) but  from  such  a  transparent  positive  may  be  obtained 
enlarged  negatives.  The  enlargement  depends  upon  the  ca- 
pacity of  the  lens  of  the  camera.  The  bellows  part  of  the 
latter  admits  of  greater  elongation  and  correlative  lateral  ex- 
pansion than  that  of  the  ordinary  camera.  As  soon  as  we 
have  found  the  distance  of  equal  conjugate  foci,  as  before  di- 
rected, then  by  diminishing  the  distance  between  the  posi- 
tive and  the  lens,  we  increase  the  distance  between  the  lens 
and  the  new  negative.  (The  transparent  positive  is  placed 
in  the  opening  in  front  of  the  lens,  where  originally  the  ne- 
gative was  placed.)  But  in  the  same  proportion  as  this  dis- 
tance is  increased,  in  like  manner  is  the  new  negative  en- 
larged. The  amount  of  enlargement*  will  depend,  as  soon 
as  the  camera  is  arranged,  upon  the  perfection  of  the  lens, 
which,  be  it  ever  so  good,  has  to  be  stopped  down  to  a  small 
aperture,  in  order  to  overcome  spherical  aberration,  which 
causes  distortion,  and  detracts  from  the  sharpness  on  the 
peripheral  parts.  With  the  bright  light  of  the  sun  there  is 
no  difficulty  in  thus  obtaining  a  negative  magnified  ten  times 
diametrically  with  such  a  lens,  and  in  a  very  reasonable 
time.  Thus  a  stereoscopic  portrait  or  view  maybe  enlarged 
into  a  cabinet-sized  picture  or  landscape,  with  but  a  small 
expenditure  of  time  and  expense.  Nor  is  ft  large  lens  re- 
quired for  this  operation.  The  same  lens  with  which  the 
original  negative  was  taken  may  be  applied  to  the  purposes 
of  enlargement.  In  making  enlarged  negatives,  however,  we 
require  particularly  a  greater  amount  or  a  greater  intensity 

*  Vide  Chapter  for  the  table  of  distances  and  magnitudes. 


158 


ENLARGEMENT  OF  NEGATIVES. 


of  light,  so  that  with  a  given  light  the  exposure  must  be  so 
much  the  longer.  In  such  cases,  then,  where  the  enlarge- 
ment is  as  great  as  before  mentioned,  it  is  advisable  to  con- 
struct a  system  of  reflectors  in  front  of  the  aperture  for  the 
reception  of  the  negative  or  positive. 

Reflectors  used  as  Condensers  of  Light. 
Let  the  aperture  for  the  negative,  etc.,  be  four  inches 
square ;  then  construct  a  frustum  of  a  pyramid  out  of  four 
pieces  of  silvered  glass,  of  the  following  dimensions  :  The  nar- 
row end  of  each  piece  is  four  inches,  the  broad  end  is 
inches;  the  length  of  either  side  is  21T5^r  inches.  Fix  these 
pieces  of  glass  in  a  tin  frame,  with  the  silvered  side  inward, 
and  attach  the  frustum  to  the  aperture  for  the  negative. 
When  the  latter  or  a  transparent  positive  is  in  its  place, 
turn  the  camera  (which  for  this  purpose  must  be  fixed  upon 
a  universal  joint)  toward  the  sun ;  it  will  be  found  that  the 
intensity  of  the  light  has  been  greatly  increased.  Such  a 
condensing  reflector  is  calculated  to  condense  all  the  rays 
that  fall  upon  it,  either  by  one  or  two  reflections,  so  that 
they  all  fall  upon  the  negative.  But  the  amount  of  light 
that  impinges  directly  upon  the  larger  base  of  the  frustum 
is  at  least  thirteen  times  greater  than  that  which  falls  upon 
the  smaller  base ;  and  if  there  were  no  loss  of  actinic  power 
by  reflection,  the  light  condensed  on  the  negative  would  be 
thirteen  times  more  than  would  impinge  upon  it  without  the 
aid  of  the  condensers.  If  then  the  light  be  increased  by  ten 
times  in  intensity,  and  the  picture  be  enlarged  by  ten  times, 
the  time  of  exposure  would  remain  the  same. 


CHAPTER  XXVI. 


TRANSPARENT  POSITIVES  BY  CONTACT  BY  THE  WET  PROCESS. 

In  this  operation,  as  in  the  preceding,  a  very  bright,  sharp, 
clear  negative  is  required.*  Transparent  positives  by  direct 
contact  are  obtained  best  by  dry  collodion  plates  ;  they  can, 
however,  be  prepared  as  follows :  Let  the  negative  be  var- 
nished and  thoroughly  dry.  Place  it  in  the  plate-holder,  as 
you  would  the  sensitized  collodion  plate.  Next  cut  out  a 
piece  of  thin  writing-paper  of  the  same  size  as  the  negative, 
and  then  cut  out  of  this  an  interior  piece  of  the  same  shape, 
thus  leaving  a  margin  all  round  of  about  a  quarter  of  an  inch 
in  width.  Place  the  marginal  rectangle  upon  the  negative, 
and  see  that  it  lies  in  contact  all  round.  Now  prepare  a  col- 
lodion plate  ;  sensitize  it,  and  allow  it  to  drain  thoroughly  ; 
then  place  it  also  in  the  plate-holder,  and  in  contact  with  the 
margin  of  paper,  and  close  the  slide  and  shutter.  Previously 
a  cylinder  of  thin  wood,  blackened  with  ink  within,  is  pre- 
pared with  grooves  at  one  end  for  the  reception  of  the  plate- 
holder,  and  open  at  the  other  extremity  for  the  reception  of 
the  light.  Such  a  cylinder  may  be  six  feet  in  length.  The 
object  in  view  is  to  obtain  only  direct  and  parallel  rays  of 
light,  to  counteract  the  effect  arising  from  the  imperfect  con- 
tact between  the  wet  plate  and  the  negative.  Direct  the 
open  end  of  the  cylinder  to  a  white  cloud,  and  then  draw 
the  slide  for  a  moment,  that  is,  a  fraction  of  a  second,  and 
close  it  again.  Probably  this  may  be  too  much  exposure,  in 
which  case  it  will  be  well  to  paste  a  sheet  of  white  paper 
over  the  end  of  the  cylinder,  in  order  to  moderate  the  action 
of  light.  The  plate  is  afterward  taken  out,  developed,  black- 
ened, and  fixed,  as  already  described. 

On  removing  the  plate  from  the  holder,  the  marginal  pa- 
per will  probably  adhere  to  the  wet  collodion  ;  if  so,  remove 
it  carefully,  and  lay  it  on  a  flat  surface  to  dry.  It  is  possi- 
ble too,  owing  to  the  inequality  of  surface,  that  the  negative 
has  been  wetted  by  the  superincumbent  wet  plate,  in  which 
case  it  must  be  carefully  washed  in  rain-water,  and  dried. 
Without  the  long  cylinder,  oblique  rays  would  enter  from 
all  sides,  and  destroy  all  the  sharpness  of  the  picture  by  pro- 
ducing thick  lines  out  of  thin  ones.  Whereas  in  the  man- 
ner prescribed,  vertical  rays  alone  are  admitted  to  the  bot- 
tom, and  entering  perpendicularly  are  not  refracted. 


CHAPTER  XXVII. 


COLLODION"  NEGATIVES  OR  POSITIVES   COPIED  FROM  COLLO- 
DION OR  PAPER  POSITIVES. 

In  this  chapter  will  be  described  the  method  of  copying 
photographic  or  typographic  prints.  Three  things  are  abso- 
lutely requisite  in  order  to  secure  a  good  copy ;  these  are,  as 
before,  a  good  lens,  good  light,  sharp  focussing. 

For  the  purpose  of  copying  I  invariably  use  the  full  blaze 
of  the  sun.  Some  artists  pretend  that  the  system  is  false. 
They  take  their  ideas  from  the  effects  produced  on  solid  ob- 
jects, where  the  contrasts  are  so  immensely  exaggerated ; 
and  they  do  not  bear  in  mind  that  on  a  flat  surface  there  can 
be  no  shadows,  because  there  are  no  prominences.  All  the 
contrast  that  can  possibly  be  obtained  in  the  copy,  exists  al- 
ready in  the  original. 

Upon  a  light  built  table  or  board,  two  inches  wider  than 
the  camera,  nail  down  on  either  side  a  ledge  of  wood,  within 
which  the  camera  can  slide  longitudinally.  At  one  foot's 
distance  from  one  end  erect  a  piece  of  board  of  the  same 
width  as  the  long  board,  and  a  foot  high ;  let  it  be  fixed  per- 
pendicular to  the  board  and  to  the  direction  of  the  ledges, 
by  means  of  triangular  braces  near  the  end  of  the  long  board. 
On  the  side  fronting  the  camera,  construct  two  beveled 
ledges,  one  on  either  side,  perpendicular  to  the  base-board, 
of  half-inch  material ;  within  this  a  piece  of  half  inch  board, 
six  inches  wide,  is  correctly  adjusted  by  planing,  so  as  to 
slide  up  and  down  with  facility ;  on  its  surface  on  either  side 
is  a  similar  bevelled  ledge  running  horizontally,  in  which  an- 
other thin  piece  is  made  to  slide  with  ease.  This  last  piece 
is  the  holder  of  the  print  to  be  copied.  By  the  construction  it 
will  be  seen  that  the  holder  admits  of  motion  vertically  and 
horizontally,  and  that  thus  the  print  can  be  accurately  ad- 
justed in  a  correct  position  in  front  of  the  lens,  so  that  the 
center  of  the  print  and  the  axis  of  the  lens  coincide.  The 
print,  too,  will  thus  be  parallel  with  the  ground  glass  in  the 
camera.    Small  slips  of  tin  plate  are  screwed  on  the  surface 


COPYING   PHOTOGRAPHIC  PRINTS. 


161 


of  the  holder,  in  order  to  clamp  down  the  print,  and  to  pre- 
vent any  unevenness  on  its  surface  by  cockling  from  the 
heat.  Pins  or  tacks  are  inadmissible  here,  because  of  the 
shadows  produced  by  them  on  the  print  to  be  copied.  As 
soon  as  this  mechanical  contrivance  is  complete,  slide  the 
camera  up  to  the  holder,  and  adjust  the  latter  so  as  to  bring 
its  center  in  front  of  the  cap  of  the  lens,  and  with  a  pencil 
draw  a  circle  around  the  cap  and  upon  the  surface  of  the 
holder.  Whilst  the  slides  are  in  this  position,  mark  the  verti- 
cal and  the  horizontal  slide,  so  that  at  any  time  afterward  the 
holder  can  be  brought  into  position  with  great  facility.  The 
holder  is  now  taken  out,  and  the  print  to  be  copied  is  fixed, 
so  that  its  center  coincides  as  near  as  can  be  with  the  cen- 
ter of  the  circle ;  it  is  placed  upside  down,  so  that  its  four 
boundaries  are  vertical  and  horizontal.  Now  slide  the  print- 
holder  into  its  place,  and  slide  back  the  camera  until  the  pic- 
ture on  the  ground  glass  is  of  an  exactly  equal  size  with  the 
original.  A  microscope  is  required  in  this  operation,  in  or- 
der to  focus  with  the  utmost  accuracy.  Do  not  despise  the 
microscope,  it  is  almost  indispensable.  Focus  whilst  the  sun 
is  shining  upon  the  picture.  Use  a  very  small  stop.  Let  the 
sun  shine  from  one  side  slightly,  with  your  back  turned  to- 
ward this  orb.  The  most  agreeable  time  to  copy  by  this 
method  is  early  in  the  morning ;  the  light  is  then  clear,  and 
by  turning  the  table  on  one  side,  the  rays  illumine  the  object 
very  brilliantly,  and  without  any  haze  ;  turn  the  table  always 
so  that  no  shadow  of  the  camera  or  lens  falls  upon  the  ob- 
ject. As  long  as  the  sun  shines,  you  can  thus  copy,  and  copy 
perfectly ;  the  morning  hours  being  personally  more  agree- 
able, photographically  perhaps  not  as  effective  as  toward  noon. 
The  time  of  exposure  will  vary  according  to  the  power  of  the 
lens,  the  size  of  the  diaphragm,  and  the  magnitude  of  the 
copy.  With  a  lens  of  three  inches  focus,  of  C.  C.  Harri- 
son's manufacture,  with  a  diaphragmatic  aperture  of  one  third 
of  an  inch,  and  when  the  copy  is  equal  to  the  original,  an  ex- 
posure of  fifteen  seconds  will  produce  a  rich  negative.  The 
same  conditions  remaining,  the  one  fourth  orthoscopic  lens  of 
Voightlaender,  whose  focus  is  about  twelve  inches,  will  re- 
quire an  exposure  of  between  two  and  three  minutes  to  pro- 
duce the  same  effect. 

By  the  first-named  lens,  an  ambrotype  or  melainotype  will 
require  only  two  or  three  seconds. 

By  adhering  cautiously  to  the  rules  prescribed,  and  above 
all  things  by  very  accurate  focussing,  and  by  taking  care  that 
the  surface  of  the  photograph,  plate,  or  print  is  perfectly 


162 


COPYING   PHOTOGRAPHIC  PRINTS. 


smooth,  and  in  a  plane  parallel  with  the  ground  glass,  copies 
can  be  obtained  that  can  scarcely  be  distinguished  from  the 
originals.  But  a  very  slight  undulation  on  the  surface  of 
the  print,  or  deviation  from  parallelism  is  sensibly  observ- 
able when  the  conjugate  foci  are  equal,  and  much  more  so 
when  the  copy  is  amplified.  The  camera,  when  once  ad- 
justed for  the  day,  is  strapped  down  firmly  to  the  board,  so 
that  the  conditions  of  focussing  can  not  be  altered  by  insert- 
ing the  tablet,  etc.  It  is  necessary  to  cover  the  whole  cam- 
era, and  especially  the  posterior  opening,  with  a  dark  cloth, 
lest  a  single  ray  might  penetrate  into  the  interior.  Close 
the  lens  always  with  the  cap  before  you  take  out  or  put  in 
the  slide,  because  it  is  easier  to  move  the  cap  than  the  slide. 
After  the  slide  has  been  taken  out,  wait  until  all  oscillation 
or  vibration  has  ceased,  before  you  remove  the  cap.  Per- 
form all  your  motions  in  this  operation  firmly,  but  with  gen- 
tleness, not  roughly  and  in  haste.  Whilst  the  ground  glass  is 
out,  place  it  where  no  reflection  can  interfere  with  the  print 
to  be  copied.  The  board  on  which  the  camera  slides,  as  also 
all  the  other  parts,  had  better  be  stained  black,  or  of  some 
neutral  tint. 

If  the  light  of  the  sun  could  be  directed  through  a  long 
cylindrical  opening,  and  then  applied  directly  to  the  illumin- 
ation of  the  print,  without  interference  from  reflections  in  all 
directions,  the  operation  would  be  neater  and  more  effectual. 

Where  copying  has  to  be  performed  by  diffused  light,  this 
light  must  be  small  in  quantity,  proceeding  from  a  single 
pane  of  glass,  as  reflected  from  a  white  cloud  or  a  white 
sheet,  and  all  reflections  must  be  carefully  avoided.  The 
management  of  the  light  in  copying  is  reduced  to  very  sim- 
ple conditions — a  single  light  is  all  that  is  required— no  more 
contrast  is  required  ;  see  that  none  is  communicated  by  unne- 
cessary and  extraneous  shadows  from  neighboring  bodies, 
caused  by  secondary  light.  A  single  light,  where  there  are 
no  bodies  in  its  direction  to  the  print,  will  produce  no  shadow, 
consequently  all  shadows  must  proceed  from  secondary  lights ; 
shut  up,  therefore,  every  aperture,  excepting  the  one  which 
is  to  illumine  the  print  or  type  to  be  copied.  These  precau- 
tions will  bring  with  them  success ;  the  neglect  of  them  will 
cause  you  to  quit  copying  with  disgust  for  want  of  success. 
With  such  a  contracted  light,  the  illumination  can  not  by 
any  means  approach  that  produced  by  the  direct  rays  of  the 
sun ;  the  consequence  will  be  firstly  the  necessity  of  using  a 
large  diaphragm,  and  of  thus  diminishing  the  sharpness  of 
the  copy ;  and,  secondly,  of  increasing  the  length  of  the  expu- 


COPYING  PHOTOGRAPHIC  PRINTS.  163 

sure.  The  difference  of  illumination  in  copying  and  in  di- 
rect portraiture  is  very  distinct ;  for  the  latter  purpose  a 
single  light  without  reflection  will  not,  can  not  succeed ; 
whereas  for  copying,  more  lights  than  one  would  be  not  only 
so  much  more  than  sufficient,  but  at  the  same  time  probably 
in  most  cases  injurious.  Do  not,  therefore,  confound  the 
two  operations,  and  blame  the  light  for  your  mismanagement 
of  it,  for  in  nine  cases  out  of  ten  your  want  of  success  is  to 
be  attributed  to  this  mismanagement. 
9 


CHAPTER  XXVIII. 


STE R  E  0 GRAPHIC  NEGATIVES  AND  LANDSCAPE  PHOTOGRAPHY, 

Hereafter  I  shall  devote  a  chapter  to  the  stereograph 
and  its  philosophy ;  in  this  I  shall  simply  give  plain  instruc- 
tions for  taking  the  stereoscopic  negatives  by  the  wet  collo- 
dion process.  For  in-door  work,  and  for  out-door  scenery  where 
the  objects  are  close  at  hand,  a  camera  is  required,  which  is  fur- 
nished with  two  lenses  of  short  focus,  and  of  exactly  equal 
power,  for  the  production  of  stereoscopic  negatives.  These 
lenses  are  fixed  in  the  same  horizontal  line ;  and  about  two 
inches  and  a  half  is  the  distance  between  their  centers.  Each 
lens  can  be  attached  to  a  separate  slide,  so  that  this  distance 
can  be  slightly  increased  to  two  inches  and  three  quarters, 
if  found  necessary.  In  the  camera  there  is  a  vertical  septum 
in  the  middle  which  divides  it  into  two  halves,  one  for  each 
lens.  This  septum  is  nearly  in  contact  with  the  collodion 
and  consequently  makes  a  division  line  between  the  two 
images,  which  are  taken  on  the  same  glass.  The  glasses  for 
stereoscopic  negatives  are  seven  inches  long  by  three  and  a 
half  wide  ;  I  should  prefer  them  eight  inches  by  four,  in  or- 
der to  have  room  for  blunders  and  mishaps  on  the  edges 
The  operation  of  focussing  is  the  same  here  as  before,  only 
that  there  are  two  lenses  to  be  adjusted.  Fix  upon  a  cer 
tain  object  which  is  to  be  the  central  or  most  important  one 
and  turn  the  camera  so  that  it  is  seen  in  the  center  of  one  o 
the  pictures  of  the  ground  glass.  Where  architectural  ob 
jects  occur  in  such  pictures,  the  camera  must  be  perfectly 
horizontal,  if  you  intend  the  vertical  lines  to  be  vertical  in 
the  negative.  If  it  happen  that  such  architectural  objects 
can  not  easily  be  comprehended  in  the  negative,  without  tilt- 
ing the  camera,  use  this  expedient ;  for,  after  all,  the  distor- 
tion which  it  produces  on  the  print  can  be  rectified  in  some 
measure  afterward,  by  tilting  the  print  in  the  stereoscope  to 
the  same  amount.  If  portraits  are  to  be  the  principal  things 
they  must  be  placed  in  such  a  position  artistically  and  photo- 
graphically as  to  appear  well,  and  at  the  same  time  in  perfect 


STEEEOGRAPHIC  NEGATIVES. 


165 


focus;  if  certain  objects  are  to  be  preeminent  in  esteem,  di- 
rect your  attention  upon  them  when  focussing,  and  regard  the 
rest  as  secondary ;  and  finally,  if  the  whole  landscape  is  the 
object,  divide  up  the  focus,  or  focus  in  such  a  manner  that 
the  view  as  a  whole  is  tolerably  sharp ;  this  can  easily  be 
done  by  focussing  an  object  at  some  distance,  and  by  exclud- 
ing all  near  objects  from  the  print.  In  such  cases,  however, 
we  require  long-focussed  lenses.  For  in-door  operations  the 
portrait  combinations  are  used  ;  for  landscapes  a  pair  of  trip- 
lets, or  of  ordinary  view  lenses,  produce  excellent  results, 
The  globe  lens  of  C.  C.  Harrison  is  all  that  can  be  desired 
for  field  work  ;  it  comprehends  a  larger  angle  than  almost  any 
other  lens,  and  produces  an  irreproachable  picture.  Ross,  Dall- 
meyer,  and  Grubb  manufacture  stereoscopic  lenses  for  land- 
scape photography,  with  which  instantaneous  pictures  can  be 
produced,  and  which  in  all  other  respects  are  highly  com- 
mended by  the  intelligent  amateurs  of  Great  Britain.  Jamin's 
view-lenses  produce  very  neat  results,  and  are  besides  lower 
in  price  than  those  already  alluded  to. 

In  the  ordinary  stereoscopic  negative,  as  in  every  negative, 
the  pictures  are  laterally  inverted,  and  when  printed,  this  in- 
version is  corrected  only  for  each  picture  individually,  for 
the  right-side  picture  is  still  inverted  and  in  the  place  of  the 
left-side  picture.  In  consequence  of  this,  the  printed  stereo- 
graphs have  to  be  cut  apart,  and  mounted  so  that  the  right- 
hand  photograph  is  placed  on  the  right  side,  and  the  left- 
hand  photograph  on  the  left  side.  When  taking  pictures  of 
still  life,  as  also  others,  where  the  living  objects  are  not  in 
motion,  it  is  very  easy  to  manage  matters  so  as  to  invert  the 
photographs  on  the  negative.  The  method  is  as  follows  : 
Take  a  large-sized  camera-stand,  allowing  sufficient  space 
for  the  camera  to  slide  laterally.  Placing  the  camera  in  the 
right-hand  corner,  focus  the  left-hand  lens.  Next  slide  the 
camera  gently,  or  lift  it  up  and  place  it  in  the  left  corner, 
and  focus  the  right-hand  lens.  The  space  between  the  cen- 
ters of  the  two  pictures  thus  focussed  must  be  about  two 
inches  and  three  quarters.  Whilst  the  camera  is  in  this  posi- 
tion on  the  left  side,  insert  the  sensitized  plate,  take  out  the 
slide,  uncover  the  right-side  cap  for  a  second  or  two,  and 
take  this  picture.  Then  close  up  the  lens,  lift  up  the  camera 
gently  and  place  it  on  the  right  side.  In  this  position  un- 
cover the  left-side  lens  for  the  same  length  of  time.  In  this 
way,  and  In  the  space  of  ten  seconds  or  so,  the  two  pictures 
can  be  taken  in  a  proper  condition  for  printing  so  as  to  pro* 
duce  a  non-inverted  stereograph.    For  such  work  it  would 


166 


STERE  O GRAPHIC  NEGATIVES. 


be  no  difficult  task  to  contrive  a  slide  by  which  a  single  lens 
would  be  all-sufficient ;  that  is,  when  the  camera  is  on  the 
left  side,  the  lens  must  slide  to  the  right  side,  and  vice  versa 
on  the  right  side. 

As  soon  as  the  negative  is  thus  taken,  it  has  to  be  devel- 
oped before  it  gets  dry.  The  development  and  fixing  can 
be  performed  in  a  dark  tent  specially  arranged  for  such  pur- 
poses. Various  contrivances  have  been  adopted  in  landscape 
photography  for  these  operations.  For  my  own  part  I  con- 
sider a  simple  hand-cart,  with  iron  rods  from  corner  to  cor- 
ner diagonally,  in  the  form  of  semi-ellipses,  and  covered  with 
a  balloon-shaped  tent,  a  very  practical  accommodation.  But 
each  successful  photographer  is  somewhat  of  a  genius,  and 
can  easily  arrange  a  dark  chamber  according  to  his  own  taste 
and  materials  on  hand. 

Negatives  thus  taken  and  fixed  are  placed  carefully  away 
in  slides  where  they  can  not  be  injured  during  transport- 
ation home.  In  the  evening,  or  the  next  day,  or  at  any  con- 
venient time,  the  negatives  are  examined ;  if  clear,  transpar- 
ent in  the  lights,  and  sufficiently  intense  in  the  shades,  they 
are  varnished.  On  the  contrary,  if  the  opacity  of  the  shadows 
is  not  deep  enough,  although  the  appropriate  gradation  ex- 
ists between  the  lights  and  shades,  it  will  then  be  deemed 
necessary  to  proceed  to  intensification.  Previously  the  edges 
of  the  negatives  must  be  varnished  to  the  depth  of  one  tenth 
of  an  inch  upon  the  collodion,  to  prevent  its  peeling  off  dur- 
ing the  operation.  This  is  effected  by  dipping  the  quill  end 
of  a  feather  into  the  varnish,  and  then  running  along  the 
edge  of  the  collodion  and  of  the  glass,  with  this  portion  of 
the  feather  slightly  inclined,  so  that  the  varnish  does  not  drop 
off,  a  sufficient  quantity  is  attracted  upon  the  collodion  as  you 
proceed.  After  this  put  the  negatives  aside,  that  the  varnish 
may  become  thoroughly  dry  and  hard.  As  soon  as  it  is  dry, 
immerse  the  plates  in  rain-water,  and  allow  them  to  remain 
there  for  about  a  quarter  of  an  hour,  by  which  time  the  col- 
lodion film  will  have  become  saturated  with  this  fluid.  Now 
you  may  commence  the  intensifying  process,  as  before  de- 
scribed in  the  chapter  on  collodion  negatives. 

Instantaneous  Stereographs. 
There  is  no  branch  of  photography  that  has  so  intensely 
attracted  the  attention  of  wealthy  and  intelligent  amateurs 
as  that  of  stereography ;  on  this  account  we  owe  to  them 
most  of  the  discoveries  in  the  art ;  and  the  new  incitement 
that  has  arisen  in  this  department,  that  of  Instantaneous  Ac- 


STEREOGRAPHIC  NEGATIVES. 


167 


tinsim,  has  communicated  a  new  impulse  from  which  we  de- 
rive fresh  deductions  and  new  results.  The  co-laborers  in  ste- 
reographic  pursuits  in  Europe,  but  more  especially  in  Great 
Britain,  beginning  with  royalty  downward  to  the  rural  gen- 
try, are  very  numerous,  very  intelligent,  and,  best  of  all,  very 
communicative.  They  take  out  no  patents  for  their  discov 
eries,  they  make  no  commerce  with  secrets,  odious  things 
which  noble  minds  eschew.  It  is  to  such  a  goodly  host  of 
fellow-soldiers  in  the  stereographic  camp  that  we  must  attri- 
bute the  riches  of  our  knowledge.  That  light  can  act  acti- 
nically in  the  twinkling  of  an  eye  is  no  tax  upon  cultivated  con- 
ceptions ;  for  in  this  same  wink,  which  to  us  is  instantaneous, 
Light  has  run  round  the  earth  several  times ;  in  this  twink- 
ling, Light  has  seen  more  than  man  in  his  age  can  ever  see ; 
in  this  twinkling,  millions  of  fresh  portions  of  light  have 
impinged  on  the  model,  and  have  rebounded  to  the  lens  and 
through  it,  and  have  nestled  upon  the  sensitized  film — we 
are  justified  then  in  expecting  that  instantaneity  in  photo- 
graphy is  feasible.  The  sole  questions  present  themselves  : 
What  film  is  sensitive  enough  to  receive  it  ?  What  deve- 
loper refined  enough  to  produce  the  reduction  ?  The  ques- 
tions are  answered  by  facts.  Instantaneous  stereographs  ex- 
ist in  great  number,  and  the  artists  that  produced  them  have 
bequeathed  to  the  public  their  modus  operandi.  I  can  not 
do  better  than  quote  a  few  instantaneous  processes.  All 
amateurs  agree  in  certain  particulars,  which  conduce  to  suc- 
cess. The  light  must  be  very  bright ;  the  atmosphere  very 
clear  /  the  glass  very  clean  /  the  collodion  very  ripe  ;  the  de- 
veloper very  sensitive,  and  the  lens  very  well  corrected,  and 
capable  of  producing  a  sharp  picture  with  a  large  diaphragm; 
the  shorter  the  focus  the  better  within  proper  bounds. 

Instantaneous  Process  of  Lieutenant-  Colonel  Stuart  Wbrtley. 


The  pyxoxyline  is  first  steeped  in  the  iodo-bromized  alcohol, 
and  the  ether  then  added. 


Iodized  by  leaving  a  couple  of  coated  plates  in  the  bath  for 
several  hours ;  acidified  at  the  rate  of  from  two  to  three 


Collodion. 


Ether,  

Alcohol,  spec,  grav.,  .802, 
Iodide  of  lithium,  .  .  . 
Bromide  of  lithium,  .  . 


1  ounce. 

.  2£  ounces. 

15  grains. 

.  6£  grains. 


Silver  Bath. 

Re-crystallized  nitrate  of  silver,  .  35  grains. 
Distilled  water,   1  ounce. 


168 


STEREO  GRAPHIC  NEGATIVES, 


drops  of  nitric  acid  to  the  ounce  of  bath.  Leave  the  plate 
in  the  bath  longer  than  you  would  if  the  collodion  contained 
only  iodine. 

Develope? 

Sulphate  of  iron,  2  ounces. 

Distilled  water,  12  ounces. 

Dissolve, 

Acetate  of  lead,  24  grains 

Water,  2£  ounces 

Dissolve. 

Mix  the  above  solutions,  and  when  the  precipitate  has  all 
settled,  decant  off  very  carefully,  and  then  add : 

Formic  acid,  (pure,)   .    .    ...    .    2-|  ounces. 

Acetic  ether,  6  drachms. 

Nitric  ether,  6  drachms. 

From  this  stock-developing  solution  take  as  much  as  is  re- 
quired, and  add  acetic  acid,  according  to  the  temperature,  gen- 
erally in  about  the  same  quantity  as  the  formic  acid.  The 
developer  is  kept  on  the  plate  until  the  necessary  detail  is 
brought  out ;  after  which  the  plate  is  well  washed  and  fixed 
with  a  weak  solution  of  cyanide  of  potassium. 

Intensijier. 

Pour  on  a  saturated  solution  of  bichloride  of  mercury ;  as 
soon  as  the  proper  color  is  attained,  the  plate  is  thoroughly 
washed,  and  a  five-grain  solution  of  iodide  of  ammonium  in 
water  is  poured  on  and  off  until  the  desired  depth  has  been 
attained.  (The  reader  will  comprehend  the  rationale  of  this 
proceeding  by  carefully  perusing  my  remarks  on  this  subject 
in  a  preceding  chapter.)  After  this  the  following  solutions 
are  used : 

No.  1.    Pyrogallic  acid,  .    .    .    .    12  grains. 

Water,  1  ounce. 

No.  2.    Citric  acid,  50  grains. 

Nitrate  of  silver,    .    .    .    .10  grains. 

Water,  1  ounce. 

Pour  a  few  drops  of  No.  2  into  No.  1,  and  pour  on  and  off 
until  the  negative  has  assumed  the  required  density.  After 
which  wash  the  plate  thoroughly  in  several  waters,  dry  and 
varnish. 

Valentine  JBlanchard  prefers  a  bromo-iodized  collodion, 
although  under  certain  conditions  he  admits  that  a  simply 
iodized  collodion  is  more  rapid,  but  at  the  same  time  there 
is  less  contrast.    The  silver  bath  is  composed  of  re-crystal- 


STEREOGRAPHIC  NEGATIVES. 


169 


lized  nitrate  of  silver,  forty  grains  to  the  ounce  of  distilled 
water,  and  saturated  with  iodide  and  bromide  of  silver.  It 
is  always  supposed  to  be  acid,  to  which  is  added  a  small  quan- 
tity of  moist  oxide  of  silver ;  after  the  solution  has  been  suf- 
ficiently agitated,  it  is  filtered,  and  then  acidified  by  a  weak 
solution  of  nitric  acid,  containing  three  or  four  drops  of  acid 
to  one  hundred  of  water.  This  acid  solution  is  added  very 
cautiously,  until  the  picture  is  quite  clear  and  free  from  fog- 
ging. A  bath  so  prepared  is  very  sensitive  whilst  new,  and 
it  is  only  whilst  new  that  any  bath  is  likely  to  produce  in- 
stantaneous results. 

The  developer  consists  of  the  sulphate  of  the  protoxide  of 
iron,  generally  thirty,  and  frequently  fifty  grains  to  the  ounce 
of  distilled  water,  acidulated  with  glacial  acetic  acid,  because 
the  ordinary  acid  contains  impurities. 

The  negatives,  when  they  require  it,  are  intensified  with  a 
saturated  solution  of  bichloride  of  mercury  in  cold  water, 
until  the  film  is  of  a  uniform  gray  color  3  they  are  then  washed 
and  treated  with  a  solution  of  iodide  of  potassium,  (one  grain 
to  the  ounce  of  water,)  by  pouring  it  on  and  off,  until  the 
film  assumes  a  greenish-slate  color.  There  should  be  ro 
greenish  hue  on  the  wrong  side  of  the  plate,  for  this  is  an  in- 
dication that  the  strengthening  has  been  carried  too  far. 

Hockins  uses  simply  iodized  collodion ;  his  bath  contains 
thirty  grains  of  nitrate  of  silver  to  the  ounce  of  distilled 
water,  and  is  iodized  by  throwing  in  a  proper  quantity  of 
iodized  collodion ;  it  is  then  filtered.  Two  minims  of  pure 
nitric  acid  are  added  to  each  eight  ounces  of  the  bath,  which 
is  prepared  twenty-four  hours  before  using. 

The  developer  consists  of 

Formic  acid,  (strong,)  ....     2  drachms, 

Pyrogallic  acid,  20  grains. 

Distilled  water,  9J-  ounces. 

Alcohol,  i  ounce. 

This  is  kept  on  the  plate  until  the  operation  is  complete, 
Claudets  Developer. 

Pyrogallic  acid,  20  grams. 

Distilled  water,  *l\  ounces. 

Formic  acid,  1  ounce. 

Alcohol,  6  drachms. 

Instantaneous  Shutters. 

The  means  by  which  light  is  cut  off  instantaneously,  which 
means  very  quickly,  are  various,  and  many  of  them  are  very 
ingenious.    Some  of  these  shutters  are  behind  the  posterior 


170 


STEREOGRAPHIC  NEGATIVES. 


combination  in  the  lens,  and  are  so  graduated  for  other  than 
instantaneous  purposes  as  to  give  a  shorter  exposure  to  the 
sky  than  to  the  foreground.  For  my  own  part  I  prefer  sim-  " 
plicity,  and  I  use  means  in  which  I  have  been  anticipated  by 
Wilson  and  others.  My  cap  is  my  shutter.  Sometimes  I 
use  a  book.  With  both  I  have  succeeded,  and  naturally  sup- 
pose others  can  do  the  same.  I  do  not  despise  the  ingenious 
shutter. 

In  very  many  cases,  with  all  the  preparations  in  a  normal 
condition,  as  we  suppose,  success  does  not  attend  our  ma- 
nipulations. There  is  still,  therefore,  a  yearning  for  some 
method  more  reliable.  I  have  frequently  succeeded  in  taking 
instantaneous  positives,  that  could  not  be  intensified  into  re- 
spectable negatives.  But  from  a  collodion  positive  we  know 
that  a  collodion  negative  can  very  easily  be  prepared  by 
copying.  In  this  way  many  a  well-valued  view  is  obtained, 
which  otherwise  would  have  to  be  sacrificed.  On  such  oc- 
casions, therefore,  where  there  is  the  least  doubt  of  success, 
it  is  advisable  to  develop  with  the  ambrotype  developer,  con- 
taining nitrate  of  potassa,  nitrate  of  silver,  and  free  nitric 
acid — the  latter,  however,  in  very  minute  quantity.  We  shall 
thus  probably  obtain  a  good  collodion  positive  on  a  melaino- 
type  or  ferrotype  plate.  This  is  afterward  carefully  copied 
into  a  negative.  In  several  instances  I  have  obtained  a  tol- 
erable effect  by  using  solution  of  sulphate  of  iron  without 
any  acid. 


CHAPTER  XXIX. 


NEGATIVES    ON  PAPER. 

These  comprehend  the  Talbotype  or  Calotype,  and  the 
Wax-Paper  Process  of  Legray,  and  its  modifications. 

The  Talbotype  or  Calotype  Process. 

This  process  is  a  negative  on  paper.  Talbot  published,  six 
months  before  the  discovery  of  the  Daguerreotype,  his  pro- 
cess with  the  chloride  of  silver  ;  and  the  year  following  the 
Calotype,  or,  as  it  is  now  frequently  denominated,  the  Talbo- 
type, was  made  known.  The  object  is  to  obtain  a  deposit  or 
film  of  iodide  of  silver  of  a  fine  and  even  structure  upon  the 
surface  of  paper.  The  best  paper  for  this  purpose  is  of  the 
English  manufacture,  being  sized  with  gelatine,  the  foreign 
papers  being  sized  with  starch. 

There  are  two  methods  of  iodizing  : 

1st.  Float  the  papers  on  a  solution  of  iodide  of  potassium, 
and  allow  them  to  dry  ;  afterward  float  them  on  a  solution 
of  nitrate  of  silver.  By  double  decomposition,  a  film  of  iodide 
of  silver  is  formed  on  the  surface  in  contact  with  nitrate  of 
potassa. 

2d.  Add  a  solution  of  iodide  of  potassium  to  one  of  ni- 
trate of  silver.  Collect  the  yellow  precipitate,  and  dissolve 
it  in  a  strong  solution  of  iodide  of  potassium.  The  paper  is 
floated  for  a  moment  upon  this  solution  and  dried.  It  is 
then  floated  upon  water  which  decomposes  the  salt,  and 
precipitates  the  iodide  of  silver  in  a  very  finely  divided  state 
on  the  surface  of  the  paper.  The  sheets  of  paper  are  then 
dried.  Their  color  is  a  pale  yellow,  and  they  are  as  yet  not 
sensitive  to  light. 

To  Sensitize  Calotype  Paper. 
Float  the  papers,  or  rather  brush  over  their  surfaces  a  so- 
lution of  nitrate  of  silver,  containing  both  acetic  acid  and 
gallic  acid.  Acetic  acid  acts  here  as  elsewhere :  it  diminishes 
the  energy  of  the  decomposition ;  it  preserves  the  whites  of 
the  paper. 


112 


NEGATIVES  ON  PAPER. 


The  Talbotype  process  in  more  definite  terms  stands  as 
follows : 

Float  the  paper  in  the  following  solution  for  a  minute : 

Nitrate  of  silver,  60  grains. 

Distilled  water,  2  ounces. 

Hang  up  the  paper  in  a  dark  room  to  dry.    Next  float  it  in 

Iodide  of  potassium,    .....    I  drachm. 
Distilled  water,  2-J-  ounces. 

for  ten  minutes ;  afterward  it  is  soaked  in  water  for  an  hour, 
in  order  to  remove  the  excess  of  iodide,  and  then  dried.  It 
is  sensitized  by  brushing  over  it  the  following  solution : 

Nitrate  of  silver,  *  25  grains. 

Distilled  water,  4  drachms. 

Glacial  acetic  acid,  1  ounce. 

Saturated  solution  of  gallic  acid,     .    1-J  ounces. 

In  a  few  seconds  the  excess  is  allowed  to  flow  off,  and,  af- 
ter draining,  it  is  placed  between  folds  of  blotting  paper, 
when  it  is  ready  for  immediate  use.  If  the  sensitized  paper 
has  to  be  kept  some  time,  a  much  weaker  solution  of  gallo- 
aceto-nitrate  is  used  than  that  just  prescribed.  To  every 
ounce  of  the  above  solution  add  from  thirty  to  fifty  ounces 
of  distilled  water,  according  to  the  temperature  of  the  cli- 
mate and  the  time  it  has  to  be  kept. 

An  exposure  of  the  paper  in  th.e  camera  whilst  still  moist 
for  a  second  or  two  will  produce  a  latent  image,  which  is  de- 
veloped in  full  intensity  by  washing  the  paper  with  a  mix- 
ture of  four  parts  of  the  saturated  solution  of  gallic  acid,  and 
one  part  of  a  solution  of  nitrate  of  silver,  (50  grains  to  the 
ounce  of  water.)  The  image  soon  begins  to  appear,  and  is 
fully  developed  in  a  few  minutes. 

Fixing  of  the  JVec/ative. 

Immerse  the  prints  in  a  solution  of  bromide  of  potassium 
of  ten  grains  to  the  ounce,  or  in  one  of  hyposulphite  of  soda, 
as  was  afterward  indicated  by  Sir  John  Herschel,  of  one 
part  of  the  salt  to  ten  parts  of  water,  until  the  yellow  iodide 
has  been  completely  removed.  The  prints  are  finally  washed 
in  many  waters,  dried  and  saturated  with  white  wax,  which 
renders  them  transparent. 

Several  distinguished  photographers  have  improved  upon 
this  calotype  process,  amongst  whom  we  may  mention  Blan- 
quart-Evrard,  Legray,  Baldus,  Geoffray,  Tillard,  etc.  Amongst 
all  these  improvements  and  extensions  the  wax-paper  process 
of  Legray  is  the  most  extensively  employed.    For  tourists 


NEGATIVES  ON  PAPER. 


11S 


it  presents  undeniable  advantages  in  portability  of  material, 
and  less  liability  to  fracture.  The  wax,  too,  is  a  decided  pre- 
servation of  organic  matter  against  the  action  of  nitrate  of 
silver. 

Wax-Paper  Process  of  Legray. 

This  is  the  simplest  of  all  the  processes  for  taking  negatives 
on  paper.  It  differs  from  the  calotype,  inasmuch  as  the  paper 
is  first  waxed  before  sensitization  in  Legray's  process,  where- 
as in  Talbot's  the  waxing  part  of  the  operation  is  the  last. 
The  paper  suitable  for  this  process  must  be  thin,  compact, 
homogeneous,  when  viewed  by  transmitted  light,  and  the 
sizing  of  the  paper  must  have  been  carefully  performed.  The 
English  papers,  although  perhaps  the  finest,  are  not  suitable, 
from  the  fact  that  they  have  been  sized  with  gelatine,  which 
presents  great  difficulty  in  the  waxing.  Saxony  negative 
paper  is  considered  the  best. 

Waxing  of  the  Paper. 
Obtain  pure  white  wax  from  the  bleacher's,  or,  in  case  this 
can  not  be  procured,  make  use  of  the  purest  yellow  wax  that 
can  be  had.  Next  prepare  a  water-bath  in  which  water  can 
be  kept  boiling,  either  by  lamps  or  a  charcoal-fire.  On  the 
lid  of  the  water  bath  place  a  porcelain  or  metallic  plate,  and 
when  hot,  rub  the  surface  with  the  wax  until  it  is  covered 
uniformly  with  a  layer  of  melted  wax.  Place  upon  this  a 
piece  of  paper  to  be  waxed.  Rub  its  surface  in  like  manner, 
until  it  is  uniformly  covered  and  transparent ;  and  proceed  in 
this  manner  until  a  pile  of  eight  or  ten  papers  is  thus  formed. 
If  the  dish  is  sufficiently  large,  place  a  piece  of  paper  by  the 
side  of  the  pile,  and  then  if  the  uppermost  paper  on  the  pile 
is  quite  transparent  with  wax,  place  it  upon  the  dry  paper ; 
upon  this  place  another  sheet  of  unwaxed  paper,  and  then  on 
this  the  second  one  from  the  pile,  and  proceed  thus  until  all 
the  waxed  papers  are  interleaved  with  dry  sheets.  The  in- 
tention of  this  operation  is  to  get  rid  of  the  excess  of  wax. 
Repeat  this  operation  until  the  object  is  effected.  Use  a  pad 
of  cotton,  and  gentle  pressure  on  the  top  of  the  pile  as  you 
proceed,  but  be  very  careful  not  to  make  a  single  crease, 
otherwise  the  sheet  in  question  is  utterly  spoiled.  As  soon 
as  the  paper  ceases  to  shine  from  the  melted  wax,  it  is  time 
to  stop  any  further  removal  of  wax.  The  sheets  of  paper, 
that  have  served  as  interleaves,  maybe  used  in  the  prepara- 
tion of  the  next  batch  of  waxed  papers.  The  papers  thus 
prepared  are  separated,  and  when  the  wax  has  congealed  in 


174 


NEGATIVES  ON  PAPER. 


their  fibrous  structure,  they  are  put  away  for  future  use  be* 
tween  plates  of' clean  glass. 

Iodizing  of  the  Paper. 

Formula  of  Legray. 

Rice-water,*  25  ounces. 

Sugar  of  milk,  1  ounce. 

Iodide  of  potassium  or  ammonium,     3  drachms. 
Bromide  of  potassium,      ....  48  grains. 

Mix,  dissolve,  and  filter.  It  is  necessary  to  be  supplied 
with  an  abundance  of  this  bath,  in  order  that  the  papers  can 
easily  be  submerged,  in  which  there  is  considerable  difficulty 
by  reason  of  the  fatty  nature  of  wax.  This  bath  can  be  pre- 
served a  long  time  if  kept,  after  using,  in  well-stoppered  bot- 
tles. 

When  about  to  use  this  bath,  pour  it  into  one  of  the  deep 
dishes  employed  in  other  operations  in  photography,  such  as 
for  albumenizing  or  for  toning,  and  let  it  be  two  or  three  inches 
in  depth  when  poured  in. 

Take  each  paper  by  two  opposite  diagonal  corners,  and 
bending  it  into  a  hollow  curve,  immerse  first  one  of  the  two 
other  diagonal  corners,  and  then  the  other  ;  move  the  paper 
backward  and  forward,  so  as  to  get  the  fluid  over  it,  grad- 
ually lowering  the  two  corners  held  in  the  hands.  Finally, 
by  means  of  a  glass  triangle  or  bent  glass  rods,  press  the 
sheet  entirely  beneath  the  surface  of  the  liquid,  and  re- 
move all  bubbles.  Proceed  in  like  manner  with  all  the 
rest,  carefully  avoiding  all  bubbles  between  the  papers.  In 
about  two  hours  the  papers  will  be  sufficiently  impregnat- 
ed with  the  iodizing  solution ;  after  which  they  are  taken 
out  singly  by  first  raising  one  corner  with  a  glass  rod,  and 
then  seizing  this  with  the  left  hand,  it  is  removed  from  the 
liquid  and  allowed  to  drain  for  a  moment,  and  finally  hung 
upon  varnished  hooks  to  dry ;  or  the  papers  may  be  suspend- 
ed on  a  line  by  clamping  each  upper  corner  by  means  of  a 
clothes-pin.  Great  care  is  required  so  as  not  to  produce  any 
wrinkle  or  crease  in  the  papers  in  any  of  these  operations. 
Several  iodizing  solutions  have  been  proposed;  the  folic  wing 
with  whey  or  serum  is  found  to  work  well. 

*  Take  seven  ounces  of  rice  and  bruise  it ;  then  boil  it  in  seven  pints  of 
rain  or  distilled  water.  As  soon  as  the  rice  yields  beneath  the  fingers,  the 
boiling  has  been  carried  on  far  enough.  The  water  is  decanted,  and  to  this 
are  added  forty-six  grains  of  isinglass  to  each  pint  of  rice-water,  and  the  mix- 
ture is  again  boiled. 


NEGATIVES  ON  PAPER, 


175 


Whey*  or  serum,  .  . 
Sugar  of  milk,f  .  . 
Iodide  of  potassium,  . 
Bromide  of  potassium, 


25  ounces. 

4  drachms. 

3  drachms. 
48  grains. 


To  the  first  of  the  two  preceding  formulas,  containing  rice- 
water,  which  is  that  of  Legray,  the  author  of  the  process 
was  in  the  habit  of  adding  a  small  quantity  of  the  cyanide 
and  fluoride  of  potassium,  which  are  regarded  now  as  of 
little  or  no  consequence. 

When  removed  from  the  iodizing  bath,  the  papers  have 
changed  their  appearance ;  they  are  now  in  a  spongy  condi- 
tion and  devoid  of  transparence  ;  but  by  heat  they  may  be 
restored  to  their  original  state.  They  frequently  assume  a 
violet  color.  When  dry,  the  sheets  of  paper  are  placed  one 
over  the  other,  between  pieces  of  blotting-paper,  and  packed 
in  a  well-closed  card-board  box  for  future  use. 

Sensitization  of  the  Paper. 
The  alkaline  iodide  in  the  waxed  paper  is  converted  into 
iodide  of  silver  by  immersing  the  sheets  in  the  following 
aceto-nitrate  of  silver  bath  : 

Re-crystallized  or  pure  nitrate  of  silver,  ...    7  drachms. 

Glacial  acetic  acid,  7  drachms. 

Distilled  water,  12  ounces. 

Filter  the  bath  into  the  appropriate  dish  and  sensitize  one 
sheet  at  a  time,  or  at  least  do  not  place  one  sheet  over  an- 
other, and  take  care  to  break  up  all  bubbles  on  the  surface 
of  the  wax-paper.  After  remaining  two  or  three  minutes 
in  this  bath,  each  sheet  is  taken  out,  immersed  in  a  dish  of 
rain-water,  well  washed,  and  then  immersed  in  a  second. 
Afterward  it  is  taken  out,  allowed  to  drain,  pressed  between 
folds  of  bibulous  paper  until  it  is  no  longer  wet,  but  simply 

*  Whey  is  obtained  by  boiling  a  couple  of  quarts  of  skimmed  milk,  and 
then  adding,  as  soon  as  it  begins  to  rise,  acetic  acid  drop  by  drop  until  the  curd- 
ling or  coagulation  is  complete.  The  whole  is  then  poured  into  a  muslin  bag 
and  filtered.  When  it  has  cooled  down  to  about  100°  or  blood  heat,  the  white 
of  an  egg  well  beaten  is  added  and  stirred  up.  The  liquid  is  again  made  to 
boil,  and  by  the  coagulation  of  the  albumen,  the  whey  becomes  clarified.  It 
is  filtered  a  second  time,  and  is  then  ready  for  use. 

f  Sugar  of  milk  is  concentrated  whey,  or  that  part  which  crystallizes  when 
whey  is  evaporated  to  a  syrupy  consistence.  This  sugar  of  milk,  or  lactin, 
as  it  is  also  called,  is  purified  by  animal  charcoal  and  again  crystallized.  It 
forms  white,  translucent,  four-sided  prisms  of  great  hardness.  It  is  solu- 
ble in  five  or  six  times  its  weight  of  cold  water  ;  its  taste  is  feebly  sweet,  and 
feels  gritty  between  the  teeth.  It  enters  into  combination  with  the  protox- 
ide of  lead,  and  is  converted  into  grape  sugar  by  boiling  with  dilute  mineral 
acids.    It  can  be  made  to  ferment,  but  does  not  do  so  spontaneously. 


176 


NEGATIVES  ON  PAPER. 


moist.  In  this  condition  it  may  be  placed  between  twc 
pieces  of  clean  glass  and  exposed  immediately,  or  it  may  be 
gummed  along  the  edges,  and  then  pasted  upon  a  sheet  of 
card-board  and  dried  for  future  use. 

De  Champlouis  has  introduced  an  improvement  into  this 
part  of  the  process.  As  soon  as  the  sheets  are  removed 
from  the  aceto-nitrate  bath,  each  is  placed  whilst  still  moist 
on  the  glass  destined  to  receive  it  in  the  plate-holder ;  it  is 
then  carefully  pressed  on  the  surface  by  means  of  a  small 
piece  of  sponge,  in  order  to  expel  any  bubble  of  air  which, 
by  remaining  between  the  paper  and  the  glass,  might  pro- 
duce uneven  reductions.  On  the  sensitized  paper  a  sheet  of 
blotting-paper  is  in  like  manner  applied  by  the  sponge,  and 
afterward  a  sheet  of  wax-paper  or  wax-cloth,  which  sub- 
serves the  purpose  of  a  final  pressure.  These  two  sheets 
must  be  thoroughly  moistened  with  distilled  water ;  they 
form  a  sort  of  cushion,  which  is  pressed  together  by  a  second 
glass  of  the  same  dimensions  as  the  first.  The  whole  arrange- 
ment may  then  be  placed  in  the  plate-holder,  for  it  is  ready 
to  receive  the  view  immediately,  or  at  any  time  within  twelve 
days.  By  this  expedient  the  paper  dries  very  slowly  from 
the  edges  to  within.  No  washing  is  required  before  ex- 
posure, which  is  a  great  saving  of  time. 

Iodized  wax-paper,  whatever  may  be  its  color  before, 
whether  yellow,  reddish,  or  violet,  is  very  quickly  bleached 
in  the  silver  bath. 

Exposure  to  the  View,  etc. 

The  sensitized  sheets,  however  prepared,  must  be  pro- 
tected against  all  access  of  light,  otherwise  they  will  be 
utterly  spoiled.  There  are  changing-boxes  to  be  had  for 
the  reception  of  waxed  paper  sheets  as  also  for  dry  plates  ; 
these  are  so  arranged  as  to  contain  a  certain  number  of 
sheets  or  plates,  and  to  expose  one  at  a  time  without  any 
injury  to  the  rest.  Without  such  an  arrangement,  the  tour- 
ist will  be  obliged  either  to  have  as  many  plate-holders  as 
plates,  or  to  have  a  small  dark-chamber  in  which  the  hands 
can  make  the  requisite  changes  by  feel.  The  time  of  ex- 
posure of  course  is  variable,  according  to  temperature  and 
the  brilliancy  of  the  light.  Two  or  three  minutes  in  a  good 
light  will  in  general  be  sufficient ;  in  ordinary  light  on  an 
average  from  ten  to  fifteen  minutes  will  be  required. 

Development  of  the  Image. 
This  operation  may  be  performed  right  away  or  any  time 
within  twenty-four  hour**     In  extreme  cases  the  develop- 


NEGATIVES  ON  PAPER. 


Ill 


ment  may  be  postponed  for  a  week ;  but  the  best  results  are 
obtained  by  developing  immediately  after  exposure.  The 
image,  as  a  general  thing,  is  not  visible  when  taken  from  the 
plate-holder,  excepting,  perhaps,  in  parts  especially  where 
the  paper  has  been  well  washed.  The  most  constant  de- 
veloper is  that  of  Crookes. 

Heat  in  a  glass  flask  twenty  fluid  ounces  of  concentrated 
alcohol  to  near  the  boiling  point,  and  then  add  four  ounces 
and  a  half  of  gallic  acid ;  filter  this  solution  into  another 
vessel  containing  seventy-two  grains  of  glacial  acetic  acid. 
This  forms  the  stock  solution  of  gallic  acid  which  will  keep 
for  an  indefinite  time.  It  has  a  brownish  color,  but  it  is 
clear. 

When  about  to  develop  a  picture,  measure  out  two  fluid 
ounces  of  rain-water,  to  this  add  half  a  drachm  of  the  alco- 
holic solution  of  gallic  acid  and  seven  minims  of  a  solution 
of  nitrate  of  silver  containing  eighty-six  grains  to  the  ounce 
of  water. 

Th6  sheets  of  paper  are  kept  submerged  in  this  bath  for 
about  half  an  hour,  by  means  of  the  glass  rod  or  triangle, 
when  the  development  will  be  complete,  which  must  be  de- 
termined by  experience. 

De  Champlouis  develops  as  follows  : 

In  the  first  place  the  paper  is  previously  passed  through 
the  silver  bath,  in  order  to  restore  its  humidity,  if  it  is  al- 
ready dry  ;  it  is  next  placed  on  a  plate  of  window-glass  and 
floated  with  a  thin  layer  of  gallic  acid  solution  ;  the  image 
appears  with  great  rapidity,  owing  to  the  quantity  of  silver 
in  the  moistened  paper ;  notwithstanding  this,  the  operator 
can  easily  follow  the  development.  By  pursuing  this  plan, 
spots  and  other  mishaps  are  avoided.  • 

Whichever  plan  is  pursued,  the  temperature  must  always 
be  at  about  80°  ;  the  developing  solutions  can  be  used  only 
once,  and  are  then  accumulated  and  reduced.  Whilst  the 
paper  is  developing,  a  dirty  deposit  appears  gradually  to 
cover  its  surface  ;  it  need  not,  however,  cause  any  anxiety. 
The  surface,  too,  becomes  spongy  and  porous  after  develop- 
ment— a  condition  which  is  removed  afterward. 

If  the  exposure  has  been  too  short,  the  image  is  very  slow 
in  appearing,  unless  an  excess  of  aceto-nitrate  of  silver  be 
used,  and  even  then  there  is  a  want  of  vigor,  and  especially 
of  the  middle  tones.  Such  a  negative  will  produce  only 
blacks  and  whites  in  the  positives  printed  from  it. 

If,  on  the  contrary,  the  time  has  been  too  long,  the  surface 
presents  a  red  tint,  and  the  development  commences  with 


178 


NEGATIVES  ON  PAPER. 


great  rapidity  on  every  part  simultaneously,  and  soon  as- 
sumes a  uniform  shade  which  takes  away  all  contrast.  For 
this  there  is  n  ?  remedy  ;  so  that  a  short  exposure  is  prefer- 
able, because  a  certain  degree  of  vigor  in  the  latter  case,  as 
well  as  contrast,  can  in  general  be  obtained.  The  develop- 
ment is  to  be  observed,  as  it  progresses,  by  transmitted  light, 
otherwise  you  might  be  deceived  by  the  gray  deposit  already 
alluded  to,  and  think  the  negative  spoiled. 

If  the  time  has  been  about  right,  the  print  will  appear 
possessed  of  the  right  gradations  of  light  and  shade,  and  of 
proper  density  of  shade.  As  soon  as  the  darkest  parts  are 
so  opaque  as  to  prevent  an  object  from  being  distinguished 
through  them,  the  development  may  be  considered  complete. 
All  further  action  is  then  stopped  by  immersing  the  nega- 
tives in  water  and  washing  it  well  by  agitation,  or  by  plac- 
ing it  on  a  plate  of  glass  and  then  washing  it  from  the  tap, 
first  on  one  side  and  then  on  the  other. 

Fixing  of  the  Image. 
This  is  effected  by  allowing  the  paper  to  remain  for  a 
quarter  to  half  an  hour  in  a  solution  of 

Hyposulphite  of  soda,  2  ounces. 

Kain-waler,  16  ounces. 

or  until  all  the  yellow  color  on  the  white  parts  has  disap- 
peared. The  print  is  then  well  washed  as  before,  and  finally 
left  in  a  vessel  of  water  for  a  number  of  hours.  Finally  it  is 
taken  out,  allowed  to  drain,  and  dried  between  folds  of  blot- 
ting-paper. 

When  dry  the  papers  have  lost  their  brilliancy,  they  have 
a  spongy  appearance,  and  as  if  covered  with  an  infinite  num- 
ber of  small  protuberances,  such  as  are  caused  by  the  iodiz- 
ing solution.  The  brilliancy  can  be  restored  and  the  spongy 
appearance  be  removed  by  holding  the  papers  over  a  fire,  or 
by  placing  each  between  sheets  of  blotting-paper  on  a  water- 
bath,  or  finally  by  running  a  hot  iron  over  each,  so  protected 
with  bibulous  paper.  The  iron,  however,  must  not  be  hotter 
than  boiling  water.  The  wax-paper  negatives  are  now  com- 
plete, and  are  ready  for  use  ;  from  them  positives  on  paper 
are  obtained  as  from  glass  negatives.  When  not  in  use, 
they  are  preserved  in  a  portfolio. 

Geoffray^s  Process  with  Cerolein  for  taking  Paper  Negatives. 

The  author  separates  the  cerolein  from  the  myricin  and 
serin  of  bees-wax  as  follows  : 

Dissolve  five  ounces  of  yellow  or  white  wax  in  ten  ounces 


NEGATIVES  ON  PAPEE. 


179 


of  alcohol  in  a  retort,  by  means  of  heat  raised  to  the  boiling 
temperature  ;  receive  the  distillate  in  a  cool  receiver,  until 
the  wax  is  completely  dissolved.  The  melted  wax  is  then 
poured  into  a  vessel  to  cool ;  gradually  the  myricin  and  cerin 
solidify,  and  the  cerolein  remains  alone  in  solution  with  the 
alcohol,  which  is  separated  by  pouring  it  upon  a  fine  muslin 
sieve,  and  finally  being  mixed  with  the  distillate,  it  is  filtered 
through  paper.  This  forms  the  stock  solution  of  cerolein 
No.  1. 

Secondly,  dissolve  in  three  drachms  of  alcohol  (spec,  grav., 
.849)  four  drachms  of  iodide  of  ammonium,  (or  of  potas- 
sium,) twelve  grains  of  bromide,  either  of  ammonium  or  of 
potassium,  and  twelve  grains  either  of  fluoride  of  ammonium 
or  of  potassium. 

To  twelve  grains  of  freshly  prepared  iodide  of  silver  add 
drop  by  drop  of  a  concentrated  solution  of  cyanide  of  po- 
tassium, until  the  former  is  dissolved,  and  then  mix  this  with 
the  alcoholic  solution  of  the  iodides,  etc.  There  will  be  a 
deposit  of  salts  undissolved  in  this  mixture,  which  is  bottle 
No.  2. 

Of  these  two  solutions  the  author  takes,  when  about  to 
use,  about  twenty  drachms  of  No.  1  and  two  drachms  of 
No.  2,  and  filters  into  a  porcelain  dish.  This  forms  the  bath 
in  which  the  papers  are  immersed  for  about  a  quarter  of  an 
hour,  five  or  six  at  a  time,  until  the  solution  is  exhausted. 
The  papers  when  dry  have  a  rosy  tinge.  The  operations  of 
sensitizing,  etc.,  are  the  same  as  in  Legray's  process. 

Turpentine  and  Wax  Process  of  Tillard. 
White  wax,  in  small  pieces,  is  digested  in  the  essence  of 
turpentine  for  several  days ;  the  solution  is  then  decanted 
and  filtered.  To  every  three  ounces  of  this  solution  add 
seven  grains  of  iodine,  which  is  immediately  dissolved  with- 
out discoloration,  or  if  any  be  produced,  expose  the  mixture 
to  the  sun.  Now  add  about  from  forty  to  forty-five  drops  of 
castor  oil,  pure  and  freshly  made,  to  the  above  quantity  of 
wax  and  turpentine.  This  forms  the  bath  when  filtered,  in 
which  the  papers  have  to  be  immersed  foi;  five  minutes  or 
so.  They  are  then  sensitized,  when  dry,  in  the  following 
bath : 

Nitrate  of  silver,  1  drachm. 

Nitrate  of  zinc,  2-J  drachms. 

Acetic  acid,  2£  drachms. 

Water,  3  ounces. 

The  paper  is  then  washed  carefully  and  dried.  After  ex* 
posure,  the  prints  are  developed  by  immersing  them  in 


180 


NEGATIVES  ON  PAPER. 


Distilled  water,  5  ounces. 

Saturated  solution  of  gallic  acid,  .  5  ounces. 
Acetic  acid,  1  ounce. 

To  which  is  added  a  small  quantity  of  a  fresh  solution  of 
nitrate  of  silver.    This  process  is  said  to  be  very  rapid. 

As  before  mentioned,  various  improvements  have  been 
made  in  the  calotype  and  wax-paper  processes,  amongst 
which  I  shall  finally  give  the  wet-paper  negative  process  of 
Humbert  de  Molard,  owing  to  its  simplicity  and  the  rapid- 
ity of  its  action. 

Wet-Paper  Negative  Process  of  Humbert  de  Molard. 
The  papers  are  floated  for  five  minutes  on  the  following 
solution : 

Distilled  or  rain-water,  6  ounces. 

Iodide  of  ammonium,  2  drachms. 

They  are  then  taken  out,  hung  up,  and  dried.  This  paper 
will  not  keep  long,  and  must  not,  therefore,  be  prepared 
long  beforehand.  With  most  papers,  that  is,  those  which 
are  sized  with  starch,  a  violet  color  is  produced  by  this  float- 
ing, owing  to  the  free  iodine  generally  existing  in  iodide  of 
ammonium. 

When  dry  and  about  to  be  used,  float  each  sheet  on  the 
following  bath  : 


Distilled  or  rain-water,     ....  6  ounces. 

Nitrate  of  silver,   3-J-  drachms. 

Nitrate  of  zinc,  .   H  " 

Acetic  acid, .   " 


It  is  then  placed  with  its  moist  side  downward  on  a  clean 
piece  of  glass  and  exposed  to  the  object,  taking  care  to  make 
allowance  for  the  thickness  of  the  glass.  From  three  to 
thirty  seconds  will  produce  the  required  result.  The  paper 
is  next  floated  on  the  developer,  which  consists  of 

Water  saturated  with  gallic  acid,  6  ounces. 

Water  saturated  with  acetate  of  ammonia,  .    .     from  48  to  60  drops. 

The  image  appears  with  great  rapidity,  and  its  development 
has  to  be  carefully  watched.  The  washing  and  fixing  are 
performed  as  usual.  When  dry,  the  negative  prints  are 
waxed,  in  order  to  give  them  the  requisite  transparence  for 
the  printing  operation. 

Improved  Calotype  Process  by  Prichard. 
Take  a  sheet  of  iodized  Turner's  paper,  half  an  inch  wider 
and  longer  than  a  plate  of  glass  fitting  in  the  dark  slide  for 
the  dry  collodion  process  ;  pin  it  on  to  a  board  in  the  usual 


NEGATIVES  ON  PAPER. 


181 


way,  and,  with  a  glass  rod,  spread  over  the  paper  a  solution 
composed  of 


Allow  this  to  remain  on  the  paper  one  minute^  and  then,  care- 
fully and  evenly,  pour  one  ounce  of  water  over  the  paper, 
which  is  easily  done  by  holding  the  board  on  which  it  is 
pinned  slantingly,  and  take  care  that  the  lower  edge  of  the 
paper  reaches  just  beyond  the  corresponding  edge  of  the 
board.  Repeat  this  washing  a  second  and  a  third  time,  and 
then  pin  up  the  paper  to  dry,  or  it  may  be  dried  between 
folds  of  blotting-paper.  Now  turn  the  sensitized  surface 
downward  on  a  sheet  of  white  blotting-paper,  and  placing 
the  plate  of  glass  upon  the  non-sensitized  side,  with  a  little 
thick  gum  attach  the  overlapped  edges  of  the  paper  to  it.  If 
the  paper  lies  even — and  it  will  do  so  if,  when  slightly  moist, 
it  be  gummed  to  the  glass,  and  afterward  dried — it  may  then 
be  exposed  for  a  few  minutes  to  the  view.  The  time,  of 
course,  has  to  be  learned  by  experience  for  given  intensities 
of  the  light  and  the  power  of  the  lens. 

After  it  has  been  exposed,  separate  the  paper  from  the 
glass  with  a  penknife,  and  develop  the  picture  with  a  solu- 
tion of  gallic  acid,  to  which  has  been  added  two  drops  of  the 
silver  solution  to  each  drachm  of  the  gallic  acid  solution. 
The  picture  comes  out  very  quickly,  and  when  it  is  fairly 
out,  the  development  is  completed  with  the  gallic  acid  solu- 
tion alone. 

Fix  with  a  weak  solution  of  hyposulphite  of  soda ;  wash, 
dry,  and  wax  by  means  of  a  hot  iron,  white  wax,  and  blot- 
ting-paper. 

The  points  requiring  most  care  are  : 

1.  To  wash  evenly,  and  so  as  not  to  allow  any  portion  of  the 
paper  to  escape  washing,  as  such  portion  would  take  no  im- 
pression and  spoil  the  picture. 

2.  Not  to  expose  before  the  paper  is  evenly  dry. 

3.  To  be  very  careful  that  the  back  of  the  paper  is  kept 
clean  and  untouched  from  any  of  the  chemicals. 


Nitrate  of  silver, 
Distilled  water, 
Glacial  acetic  acid, 


28  grains. 
1  ounce. 
10  drops. 


CHAPTER  XXX. 


POSITIVE  PRINTING. 

Printing  on  Plain  Paper,  on  Albumenized  Paper,  on 
Arrow-Root  Paper. 

The  theory  and  practice  of  positive  printing  are  second 
only  in  time,  not  in  importance,  to  the  theory  and  practice 
of  the  negative ;  it  is  rare,  however,  that  the  same  amount  of 
care  and  labor  is  bestowed  upon  this  department  as  upon 
that  of  taking  a  negative.  We  run  all  sorts  of  risk,  make 
every  effort,  incur  immense  expenses  in  order  to  secure  a 
first-rate  negative,  and  then  frequently  abandon  the  gem  into 
the  hands  of  an  indifferent  assistant,  which  is  tantamount  in 
many  instances  to  leaving  the  negative  to  print  itself.  What 
an  analogy  exists  here  between  that  of  planting  and  culti- 
vating ;  that  of  begetting  and  of  educating !  Do  not  some 
farmers  dibble  a  hole,  insert  the  seed,  and  then  conclude  their 
labor  is  ended  ?  Do  not  some  parents  almost  come  to  the 
same  conclusion  ?  They  both  leave  the  cultivation  and  edu- 
cation of  the  young  germs  to  the  sun,  the  wind,  and  the  wea- 
ther, not  to  Providence ;  for  he  that  believes  in  Providence, 
puts  his  shoulder  to  the  wheel  and  works  for  Providence. 
In  a  manner  quite  analogous,  the  photographer  neglects  the 
execution  of  the  printing  department,  regards  the  operation 
as  secondary,  concludes  that  having  secured  a  good  negative, ' 
prints  will  grow  from  it  like  potatoes  from  the  seedling. 
This  negligence  must  be  abandoned,  and  more  vigorous  ac- 
tion commenced. 

Positive  printing  is  two-fold,  consisting  in  direct  printing 
by  the  rays  of  the  sun,  and  printing  by  development  or  con- 
tinuation ;  in  the  former  case  the  image  becomes  visible  dur- 
ing the  operation  by  means  of  light  itself ;  in  the  latter  case 
the  impression  made  by  light  is  latent,  and  is  rendered  visi- 
ble afterward  by  chemical  reduction.  The  chemical  mate- 
rials used  in  the  preparation  of  the  paper  for  the  reception 
of  the  image  are,  first,  surface  materials  for  communicating 
a  more  uniform  and  smooth  layer,  such  as  albumen,  gelatine, 


POSITIVE  PRINTING. 


183 


starch  and  gums  ;  secondly,  substances  that  undergo  some  phy- 
sical or  chemical  change  by  the  agency  of  light,  and  which  are 
mixed  with  the  surface-materials ;  these  are  the  chlorides,  bro- 
mides and  iodides  of  the  various  metals.  Paper,  so  prepared, 
is  sensitized  in  the  dark-room  in  a  bath  of  nitrate  of  silver  ; 
the  chloridized  paper,  when  sensitized,  yields  an  image  by 
the  direct  operation  of  light.  Paper,  prepared  with  the 
other  salts,  receives  an  invisible  impression  of  the  image, 
which  is  made  manifest  in  a  bath  of  gallic  acid  or  some  other 
material,  according  to  the  circumstances  of  the  case.  The 
image  obtained  by  the  direct  agency  of  light  has  a  beautiful 
color,  but  the  picture  is  not  permanent,  for  light  continues 
still  to  act  upon  the  prepared  film,  and  finally  obliterates 
the  image.  The  positive  thus  obtained,  therefore,  has  to  be 
fixed  in  the  same  manner  as  the  collodion  picture,  and  by  one 
of  the  same  fixing  solutions,  hyposulphite  of  soda.  But  the 
color  of  the  image  after  fixation  is  far  from  being  bright  and 
agreeable ;  we  have,  therefore,  to  resort  to  means  before  fix- 
ing, during  fixing  or  afterward,  by  which  the  color  can  be  re- 
stored, or  an  agreeable  color  can  be  communicated.  This 
operation  is  denominated  the  toning  of  the  picture.  The 
chemical  substances  used  m  this  operation  are :  chloride  of 
gold,  and  sometimes  nitrate  of  uranium,  together  with  cer- 
tain accessories  that  modify  the  action  of  these  two  salts, 
such  as  carbonate  of  soda,  carbonate  of  lime,  phosphate  of 
soda,  acetate  of  soda,  chlorinetted  lime,  citrate  of  soda,  etc. 
Direct  positive  printing  will  occupy  our  attention  first.  The 
subject  is  divisible  into  the  following  branches  ;  Description 
of  the  principal  materials  used ;  Preparation  of  the  paper ; 
Sensitizing  of  the  paper  ;  Printing  by  exposure  to  the  sun  ; 
Washing  of  the  prints  ;  Toning  of  the  prints  ;  Fixing  of  the 
prints ;  Washing  of  the  fixed  prints  ;  Drying  of  the  prints  ; 
Cutting  and  Mounting  of  the  prints. 

Description  of  the  Materials  used  in  Positive  Printing. 

Paper,  suitable  for  photographic  purposes,  must  be  homo- 
geneous throughout,  and  of  a  very  fine  texture.  The  surface 
particularly  must  be  uniform  and  satinized,  free  from  all 
marks  or  specks,  or  chemical  particles  which,  by  decomposi- 
tion afterward,  would  spoil  the  picture.  Such  paper  can  be 
had  of  the  different  photographic  establishments,  from  the 
various  paper-mills  of  America,  England,  France,  Germany, 
etc.  Owing  to  the  different  materials  employed  in  the  sizing 
of  the  paper,  arises  a  difference  in  the  tone  of  the  photogra- 
phic picture  ;  some  sizing  consists  of  starch,  others  of  gela- 
tine. 


184 


POSITIVE  PRINTING. 


Albumen. 


This  substance  derives  its  name  from  the  white  of  egg,  of 
which  it  constitutes  the  greatest  quantity.  It  is  found  also 
in  blood,  in  the  form  of  serum,  (the  fluid  in  which  the 
blood  corpuscles  swim,)  in  the  serum  of  milk,  in  all  serous 
secretions,  etc.  It  exists  in  two  forms,  soluble  and  insoluble. 
When  coagulated,  or  in  the  insoluble  form,  it  constitutes  a 
portion  of  most  of  the  solid  tissues  of  the  animal  frame. 
Solid  albumen  can  be  obtained  by  evaporating  either  the  se- 
rum of  blood,  (the  watery  fluid  which  separates  from  the  clot 
after  coagulation,)  or  the  white  of  an  egg  to  dryness,  at  a 
temperature  not  exceeding  120°.  The  latter  substance  must 
first  be  broken  up  thoroughly,  so  as  to  separate  the  membran- 
ous or  fibrous  material  that  holds  it  together  in  a  compact 
form,  and  then  after  subsidence  the  fluid  portion  is  decanted. 
The  dry  mass  is  a  yellow,  transparent,  tough  and  hard  sub- 
stance, consisting  of  albumen,  with  a  small  quantity  of  the 
saline  substances  that  exist  in  this  material,  and  which  may 
be  separated  by  digestion  in  alcohol  and  ether.  So  dried,  it 
swells  up  when  put  in  water  and  finally  dissolves.  Before  it 
is  dissolved,  it  may  be  heated  to  a  higher  temperature  than 
the  boiling  point  of  water  before  it  passes  into  the  insoluble 
condition ;  but  when  dissolved  in  water  and  heated  to  a  tem- 
perature between  140°  and  150°,  it  coagulates,  and  becomes 
quite  insoluble  in  water.  Albumen  in  solution  is  precipitated 
by  alcohol,  acids,  metallic  salts,  and  several  organic  bodies, 
such  as  tannic  acid  and  kreosote.  The  precipitates  of  albu- 
men by  metallic  salts  constitute  two  distinct  substances, 
namely,  albumen  with  the  acid,  and  albumen  with  the  oxide, 
of  which  generally  the  former  is  soluble  and  the  latter  insol- 
uble. Pure  albumen  is  supposed  to  be  really  an  insoluble 
substance,  but  rendered  soluble  by  the  alkalies  which  it  con- 
tains ;  for  if  the  white  of  egg,  or  serum  of  blood,  be  dissolved 
in  a  large  quantity  of  pure  water,  and  the  solution  be  exact- 
ly neutralized  by  acetic  acid,  a  flocculent  precipitate  is  ob- 
tained which  is  insoluble  in  pure  water,  but  easily  soluble 
when  the  latter  contains  a  small  quantity  of  caustic  alkali. 
So  obtained  by  precipitation,  it  has  neither  color,  odor,  nor 
taste.    Albumen  contains  in  one  hundred  parts  : 


Carbon, 
Hydrogen, 


53.5 
1.0 
15.5 
22.0 
0.4 
1.6 


Nitrogen, 
Oxygen, 


Phosphorus, 
Sulphur,  .  , 


100.0 


POSITIVE  PRINTING. 


185 


Common  dried  albumen,  not  obtained  by  precipitation,  con- 
tains, in  addition  to  common  salt,  phosphate  of  soda,  and  car- 
bonate of  soda.  It  can  easily  be  shown  that  white  of  egg 
contains  sulphur,  by  boiling  it  in  a  solution  of  caustic  potas- 
sa  and  acetate  of  lead,  when  a  black  precipitate  of  sulphide 
of  lead  will  be  formed.  The  photographic  student  will  also 
observe  that  albumen  contains  the  elements  of  ammonia, 
which  is  generated  during  the  putrefactive  decomposition  01 
this  material.  The  salts  which  it  forms  with  metallic  oxides 
are  denominated  albuminates  ;  and  the  albuminate  of  silver, 
which  is  formed  at  the  same  time  with  the  chloride  of  this 
metal  in  the  albumen  film,  is  instrumental  in  producing  the 
difference  that  exists  between  a  plain  print  and  an  albumen 
print. 

Gelatine. 

This  substance,  if  it  exist  in  nature,  has  never  yet  been  ob- 
tained otherwise  than  by  the  use  of  boiling  water  ;  it  is  sup- 
posed, therefore,  by  some  to  be  a  product  of  the  decomposition 
of  albumen  or  fibrine.  All  membranes,  such  as  the  skin,  ten- 
dons, cartilage,  hoofs,  and  bones,  yield,  when  boiled  at  a  high 
temperature,  a  solution  which,  on  cooling,  concretes  into  a 
semi-transparent  tremulous  mass.  This  substance  is  gelatine 
or  its  congener  chondrin,  (from  cartilage.)  The  jelly  obtained 
from  boiling  calves'  feet,  common  size,  isinglass,  and  common 
glue  are  familiar  examples  of  gelatine.  Isinglass  (the  dried 
swimming  bladder  of  the  sturgeon)  dissolves  in  water,  and 
yields  a  very  pure  form  of  gelatine.  When  pure  and  dry, 
gelatine  is  colorless  and  transparent ;  it  swells  and  softens  in 
cold  water,  in  which  it  is  very  sparingly  soluble ;  but  in  hot 
water  it  dissolves  very  easily.  Alcohol  and  ether  do  not  dis- 
solve it ;  it  is  precipitated  by  alcohol  from  an  aqueous  solu- 
tion. When  dry  it  can  be  preserved  for  an  indefinite  time 
without  alteration ,  but  in  a  moist  state  it  undergoes  decom- 
position, becomes  acid,  and  ceases  to  gelatinize.  Long-con- 
tinued boiling  produces  the  same  effect.  Some  metallic  salts 
produce  a  flocculent  precipitate  in  solution  of  gelatine,  so 
does  chlorine ;  but  its  most  characteristic  property  is  that  ot 
being  j>recipitated  from  a  very  dilute  solution  by  means  of 
tannic  acid,  the  only  acid  by  which  it  is  precipitated.  Act- 
ing on  this  principle,  skins  are  converted  into  leather  by  the 
process  called  tanning ;  but  skins  are  not  boiled  in  this  pro- 
cess, and  hence  it  is  supposed  that  gelatine,  after  all,  is  a  na- 
tural product. 

When  gelatine  is  digested  in  strong  sulphuric  acid,  or  in 
caustic  potassa  the  same  decomposition  is  effected.  Ammo* 


186 


POSITIVE  PRINTING. 


nia  is  iv  variably  one  of  the  products,  and  among  other  pro- 
ducts wa  may  count  sugar  of  gelatine  or  glycocine  and  leu- 
cine. 

Dry  gelatine  is  found  to  contain  in  one  hundred  parts : 

Carbon,  50.05 

Hydrogen,  6.47 

Nitrogen,  18.35 

Oxygen,  25.13 

100.00 

Amylaceous  or  Non-Azotized  Substances. 
Starch,  arrow-root,  cellulose,  gum-arabic,  etc.,  belong  to  this 
class  of  bodies.  They  are  found  in  the  vegetable  kingdom 
in  a  free  state,  and  produce  by  slight  changes  in  the  veg- 
etable organization,  a  great  variety  of  substances,  containing 
no  nitrogen,  and  differing  essentially  only  in  the  different  num- 
ber of  equivalents  of  water  with  which  they  are  combined, 
or,  as  far  as  regards  chemical  equivalents,  sometimes  not  dif- 
fering at  all ;  for  starch,  dextrin,  arrow-root,  gum-tragacanth, 
cellulose;  amidin,  all  contain  the  same  number  of  equivalents 
of  carbon,  hydrogen,  and  oxygen,  and  are  all  resolved  into 
saccharine  substances  by  treatment  with  acids. 

Starch. 

Seeds,  roots,  tubers,  and  stems  of  most  plants  contain  this 
substance  in  the  form  of  very  minute  insoluble  granules.  If 
pumpkins,  potatoes,  or  horse-chestnuts  be  rasped,  and  the 
pulp  be  then  well  washed  on  a  fine  sieve,  these  granules 
will  pass  through  the  meshes,  whilst  the  cellular  tissues  will 
be  retained  on  the  sieve.  The  powder  will  finally  subside, 
and  the  fluid  above -it  can  be  poured  off.  This  substance  is 
starch,  which  has  to  be  washed  several  times,  in  order  to  get 
rid  of  impurities,  and  especially  the  bitter  principle  peculiar 
to  certain  seeds  and  plants.  After  the  white  residue  has  thus 
been  thoroughly  purified,  it  is  dried  at  a  gentle  heat,  by  which 
it  concretes  and  cracks  into  the  form  in  which  it  generally  ex- 
ists in  commerce.  Starch  is  not  only  insoluble  in  water,  but 
also  in  alcohol.  When  examined  in  the  microscope,  these 
granules,  of  an  oblong  shape  generally,  exhibit  concentric 
rings  by  which  the  starch  granule  is  easily  designated  from 
other  powders,  and  frequently  the  granule  of  one  plant  can 
be  distinguished  from  that  of  another,  as,  for  instance,  that 
of  the  potato  from  that  of  arrow-root.  The  latter  substance 
is  the  starch  obtained  from  the  roots  of  the  maranta  arundi* 
nacea,  growing  in  the  West-Indies.   The  size  of  the  granule 


P0SIT1VJE  PRINTING. 


187 


varies  from  w^  to  -^jo  parts  of  an  inch  in  diameter.  Each 
granule  is  regarded  as  a  cell  of  concrete  and  insoluble  mate- 
rial, holding  within  a  soluble  pulp.  When  boiled,  the  cells 
are  burst  or  broken  up,  and  the  soluble  part  mixes  with  the 
water  and  forms  a  thick  gelatinous  mass,  called  amidine.  If 
the  solution  of  starch  be  dried  at  a  gentle  heat  and  then  di- 
gested in  cold  water,  the  fluid  portion  can  be  separated  from 
the  insoluble  husks  or  cells,  in  a  colorless,  transparent  form. 
A  thin  solution  of  starch  is  precipitated  by  several  bases,  as 
lime,  baryta,  and  protoxide  of  lead ;  a  large  addition  of  alco- 
hol has  the  same  effect.  Infusion  of  galls  causes  a  yellow 
precipitate  which  dissolves  when  the  solution  is  heated.  The 
best  test  of  the  presence  of  starch  is  free  iodine,  which  pro- 
duces a  beautiful  violet-blue  color  or  precipitate  in  solution 
of  this  substance.  The  blue  color  disappears  on  the  applica- 
tion of  heat,  and  returns  as  the  solution  cools. 

The  substance  called  British  gum  is  simply  starch  that 
has  been  heated  above  240°,  when  the  latter  softens  and  be- 
comes brown  and  soluble  in  cold  water.  If  a  solution  of 
starch  be  boiled  with  a  small  quantity  of  dilute  sulphuric, 
hydrochloric,  or,  in  fact,  almost  any  acid,  it  soon  becomes 
thin  and  is  then  called  dextrine.  The  sulphuric  acid  is  after- 
ward removed  by  adding  chalk  to  saturation,  and  then  by  fil- 
tering and  evaporating  the  filtrate  to  dryness.  The  substance 
thus  obtained  resembles  gum  and  is  soluble  in  cold  water. 
By  continuing  the  action  of  sulphuric  acid  and  the  boiling, 
dextrine  is  converted  into  grape-sugar.  This  conversion  is 
produced  also  in  the  act  of  germination  of  seeds  as  in  malt- 
ing. 

Gum- Arabic. 

This  substance  is  the  spontaneous  exudation  from  the  bark 
of  the  acacia  vera  and  the  acacia  arabica.  In  its  purest  and 
finest  condition,  it  is  in  the  form  of  white  or  slightly  yellow- 
ish concretions,  which  are  soluble  in  cold  water,  forming  — 
thus  a  viscid,  adhesive  solution.  The  pure  gummy  princi- 
ple, called  arabine,  is  precipitated  by  alcohol  and  by  basic 
acetate  of  lead. 

Chloride  of  Gold. 
Gold  does  not  dissolve  directly  in  hydrochloric  acid,  but 
it  enters  into  combination  very  vigorously  with  moist  chlo- 
rine, or  with  chlorine  in  the  nascent  state.    The  menstruum 
in  which  it  dissolves  is  nitro-hydrochloric  acid. 

Gold. — Symbol,  Au.    Combining  Proportion,  197.    Specific  Gravity,  19.3. 
Protoxide  of  Gold. — Symbol,  Au  0.    Combining  Proportion,  205. 
Teroxide  of  Gold. — Symbol,  Au  O3.    Combining  Proportion,  221. 
Terchloride  of  Gold. — Symbol,  Au  Cl3.    Combining  Proportion,  303. 
10 


188 


POSITIVE  PRINTING. 


Gold  dissolves  in  a  mixture  of  one  part  nitric  acid  and 
four  parts  hydrochloric  acid.  In  this  mixture  the  nitric  acid 
becomes  decomposed,  parting  with  oxygen,  which  then  de- 
composes the  hydrochloric  acid  and  combines  with  its  hy- 
drogen to  form  water,  whilst  the  chlorine  in  the  nascent 
state  combines  with  the  gold  in  the  solution.  This  is  after- 
ward evaporated  on  a  water-bath  in  order  to  drive  off  all 
excess  of  acid.  In  this  way  we  obtain  a  red-brown,  de- 
liquescent crystalline  mass  of  the  terchloride.  If  the  heat 
be  too  great,  the  salt  is  decomposed,  chlorine  is  set  at  liber- 
ty, and  a  protochloride  or  metallic  gold  is  left,  according  to 
the  temperature.  The  terchloride  is  very  soluble  in  water, 
ether,  and  alcohol.  The  solution  has  a  yellow  color  and  an 
acid  reaction ;  it  stains  the  skin  purple.  Ether  separates 
this  salt  from  an  aqueous  solution  very  effectually  by  agita- 
tion ;  and  the  mixture  ascends  and  forms  a  layer  on  the  sur- 
face of  the  water,  which  can  easily  be  separated  by  decanta- 
tion,  by  a  syringe,  or  by  allowing  the  water  solution  to  flow 
off  from  a  funnel ;  after  which  the  ether  is  expelled  and  col- 
lected by  distillation. 

Most  of  the  deoxidizing  agents  reduce  terchloride  of  gold, 
such  as  hydrogen,  carbon,  carbonic  acid,  deutoxide  of  nitro- 
gen, sulphurous  acid,  phosphorous  acid,  and  their  salts,  ter- 
chloride of  antimony,  the  proto-salts  of  iron,  many  of  the  me- 
tals, most  organic  substances,  and  oxalic  acid. 

The  crystallized  terchloride  has  a  dark  reddish-brown  color ; 
but  if  it  contains  excess  of  hydrochloric  acid,  it  has  a  bright 
yellow  color  ;  the  solutions  partake  of  the  same  color ;  the 
color,  therefore,  is  a  criterion  of  the  purity  of  this  salt.  A 
strong  solution  of  the  salt  has  a  dark  olive-green  tinge, 
which  becomes  yellow  by  dilution.  This  salt  combines  with 
the  analogous  potassium,  sodium,  and  ammonium  salts,  giv- 
ing rise  to  definite  compounds  of  these  double  salts,  which 
are  very  frequently  sold  in  commerce  for  the  true  terchlo- 
ride.   The  formulas  for  these  three  salts  are : 

Aurochloride  of  Potassium. — K  CI.  Au  Cl3  +  5  Aq. 
Aurochloride  of  Sodium. — Na  CI.  Au  CI3  +  4  Aq. 
Aurochloride  of  Ammonium. — NH4  CI.  Au  Cl3  +  2  Aq. 

All  these  salts,  as  well  as  the  double  salt  of  gold  and  cal- 
cium, are  used  in  toning.  They  are  formed  by  neutralizing 
the  hydrochloric  acid  in  excess  in  the  terchloride  by  means 
of  the  respective  carbonates  of  the  preceding  metals. 

Refuse  gold  solutions  are  reduced  in  general  by  either 
sulphate  of  the  protoxide  of  iron  or  by  oxalic  acid.  The 
brown  powder  which  subsides  is  well  washed,  first  with 


POSITIVE  PRINTING. 


189 


water,  then  with  boiling  hydrochloric  acid  ;  this  is  pure 
gold  in  a  fine  pulverulent  form,  which  can  be  used  for  gild- 
ing and  enameling,  or  for  making  pure  terchloride. 

The  gold  coins  of  the  country  are  alloyed  with  either  sil- 
ver or  copper,  which  can  be  separated  by  various  methods. 
Both  the  silver  and  copper  may  be  removed  at  the  same 
time  by  the  following  means :  melt,  for  instance,  a  gold  dol- 
lar together  with  ten  times  its  weight  of  silver  (ten  five-cent 
pieces)  in  a  crucible  ;  when  melted,  pour  it  out  on  a  clean 
stone,  and  afterward  pass  the  lump  between  a  pair  of  rollers 
so  as  to  reduce  it  to  very  thin  foil.  Digest  the  foil  in  pure 
nitric  acid,  which  will  dissolve  the  copper  and  the  silver,  and 
leave  a  residue  of  a  bright  cinnamon  color.  Wash  this  re- 
sidue, which  is  gold  in  a  very  porous  or  pulverulent  condi- 
tion, and  then  dissolve  it,  as  before  directed,  in  nitro-hydro- 
chloric  acid ;  evaporate  to  dryness,  dissolve,  and  rectify  by 
ether. 

Whenever  silver  is  alloyed  with  gold,  it  is  precipitated 
during  the  solution  in  aqua  regia  as  the  insoluble  chloride, 
which  can  be  removed  by  decantation  of  the  chloride  of  gold. 
The  copper  is  afterward  precipitated  as  the  green  carbonate 
by  adding  carbonate  of  soda  to  the  solution  as  long  as  effer- 
vescence is  produced,  which  is  separated,  in  like  manner,  by 
decantation. 

If  steel  be  dipped  in  an  ethereal  solution  of  the  terchlo- 
ride of  gold,  it  becomes  covered  with  a  film  of  reduced  gold. 
Dry  gilding  is  performed  by  coating  the  article  with  an 
amalgam  of  gold,  submitting  the  same  to  heat,  so  as  to  drive 
off  the  mercury,  and  then  burnishing  the  gilded  surface. 
An  amalgam  of  gold  consists  of  a  solution  of  gold  foil  to 
saturation.  The  article  is  first  dipped  in  a  solution  of 
nitrate  of  mercury,  and  then  covered  with  amalgam. 

The  gold  solution  for  electro-gilding  is  made  by  dissolving 
to  saturation  the  terchloride  of  gold  in  a  saturated  solution 
of  cyanide  of  potassium ;  this  solution  can  afterward  be  di- 
luted ad  libitum. 

Nitrate  of  Uranium. 
Uranium  is  a  metal  which  is  not  very  abundant ;  in  com- 
bination it  occurs  in  the  mineral  pitch  blende,  as  the  black 
oxide ;  with  silica,  oxide  of  lead  and  oxide  of  iron,  as  uran- 
mica  or  chalcolite,  and  as  uranite  in  combination  with  lime 
and  phosphorus. 

Uranium.— Symbol,  U.    Combining  Proportion,  60. 
Sesquioxide  of  Uranium. — Symbol,  U2  03.    Combining  Proportion,  144. 
Nitrate  of  the  Sesquioxide  of  Uranium. — Symbol,  U2  03,  NO5.  Combining 
Proportion,  198. 


190 


POSITIVE  PRINTING. 


This  salt  is  obtained  directly  from  pitch  blende  by  treat- 
ment with  nitric  acid.  The  ore  is  first  pulverized  and  acted 
upon  by  nitric  acid  ;  and  the  solution  is  then  evaporated  to 
dryness.  The  residue  is  then  washed  with  water,  which 
dissolves  the  nitrate  and  leaves  a  quantity  of  sulphate  and 
arseniate  of  the  sesquioxide  of  iron.  The  liquid  still  con- 
tains salts  of  copper,  lead,  and  arsenic ;  these  are  removed 
by  passing  a  current  of  hydrosulphuric  acid  through  the  so- 
lution, which  precipitates  all  these  metals.  The  solution  de- 
canted or  filtered  from  the  sulphides  of  the  above  metals  is 
evaporated  to  dryness,  and  the  residue  is  again  treated  with 
water,  which  takes  up  the  nitrate  and  leaves  a  residue  of 
sesquioxide  of  iron.  The  solution  is  now  evaporated  and 
crystallized. 

Nitrate  of  uranium  is  a  yellow  salt,  which  is  very  soluble ; 
it  contains  six  equivalents  of  water,  which  by  heat  can  be  ex- 
pelled, and  by  greater  heat  the  salt  is  decomposed.  The  al- 
kaline carbonates  all  produce  yellow  precipitates  with  the 
salts  of  the  sesquioxide ;  whilst  ferrocyanide  of  potassium 
produces  a  red-brown  precipitate.  This  salt  has  been  lat- 
terly used  in  the  toning-bath  along  with  the  ter chloride  of 
gold. 

Acetate  of  Soda — Citrate  of  Soda — Phosphate  of  Soda. 

These  three  salts  are  easily  prepared  by  adding  to  each  of 
the  acids,  acetic,  citric,  and  phosphoric,  carbonate  of  soda  as 
long  as  there  is  any  effervescence.  The  solutions  are  then 
evaporated  and  crystallized. 

Acetate  of  Soda.— Symbol,  Na  0,  C4  H3  03  +  6  HO. 
Citrate  of  Soda.— Symbol,  3  Na  0,  C12  H5  On. 
Phosphate  of  Soda.— Symbol,  2  Na  0,  HO.  P05. 

Carbonate  of  Soda. 
Symbol,  Na  0,  C02. 
This  salt  is  now  obtained  from  chloride  of  sodium  or  com- 
mon salt.  The  latter  salt  is  first  decomposed  into  sulphate 
of  soda ;  the  sulphate  of  soda  is  next  roasted  with  charcoal, 
by  which  it  is  converted  into  sulphide  of  sodium ;  and  final- 
ly the  latter  substance,  by  roasting  with  powdered  limestone 
and  coal,  is  reduced  to  carbonate  of  soda. 

Carbonate  of  Lime. 
Symbol,  Ca  0,  C02.    Combining  Proportion,  50. 
This  substance  occurs  in  great  abundance,  as  chalk,  marl, 
marble,  and  limestone.    Chalk  is  sufficiently  pure  for  the  pur- 
pose alluded  to.   When  added  to  the  terchloride  of  gold,  car- 


POSITIVE  PRINTING. 


191 


bonic  acid  is  liberated,  and  chloride  of  calcium  formed,  giv- 
ing rise  to  the  double  salt,  aurochloride  of  calcium,  which  is 
to  be  decanted  from  the  insoluble  residue.  This  salt  is 
more  easily  prepared  in  a  definite  condition  than  any  of 
the  preceding  aurochlorides  ;  and  on  this  account  its  em- 
ployment in  the  toning-bath  is  more  reliable  and  to  be  re- 
commended. 

Chloride  of  Ammonium. — Symbol,  NH4  CI.    Combining  Proportion,  52. 
Chloride  of  Sodium. — Symbol,  Na  CI.    Combining  Proportion,  58. 
Chloride  of  Potassium. — Symbol,  K  CI.    Combining  Proportion,  74. 
Chloride  of  Barium. — Symbol,  Ba  CI.    Combining  Proportion,  104. 
Chloride  of  Calcium. — Symbol,  Ca  CI.    Combining  Proportion,  63. 

All  these  chlorides  can  be  so  easily  prepared  by  saturating 
hydrochloric  acid  with  their  respective  carbonates  as  long 
as  effervescence  is  produced,  that  it  is  not  necessary  to  de- 
scribe them  separately.  There  is  this  to  be  remarked  about 
them  in  their  application  to  photography,  that  the  same 
quantity  of  either  (a  thing  which  I  need  scarcely  remark) 
will  not  produce  the  same  effect.  Of  those  already  men- 
tioned, the  chloride  of  ammonium  by  weight  requires  to  be 
used  in  the  smallest  quantity,  whilst  the  chloride  of  barium, 
when  just  twice  as  heavy,  is  only  equally  efficacious  in  pro- 
ducing a  given  quantity  of  chloride  of  silver. 

The  iodides  and  bromides,  as  also  gallic  acid,  have  been 
already  described.  We  shall,  therefore,  proceed  to  the  mi- 
nutiae of  the  manipulation  of  positive  printing  by  contact* 


CHAPTEE  XXXI. 


MANIPULATION  OF  POSITIVE  PRINTING. 

Preparation  of  Salted  Paper. 

For  sensitizing  paper  and  for  toning,  washing,  and  fixing, 
we  require  either  porcelain  or  gutta-percha  dishes  of  an  ap- 
propriate size.  These  can  be  had  of  the  city  dealers,  of  any 
size  that  may  be  needed ;  those  of  gutta-percha  are  the  best 
for  large  operations.  The  photographic-ware  baths  may  also 
be  used  for  these  purposes,  and  are  to  be  recommended  on 
account  of  their  cheapness. 

There  are  several  kinds  of  paper  in  use,  such  as  Saxony 
paper,  French  paper,  and  English  paper.  There  is  a  differ- 
ence in  the  surface  of  paper,  that  is,  there  is  a  right  side  and 
a  wrong  side.  The  smooth  or  right  side  is  the  one  which 
receives  the  sensitizing  materials ;  it  can  easily  be  distin- 
guished from  its  opposite  or  wrong  side.  Salted  paper  may 
be  either  arrow-root  or  albumenized  paper. 

Plain  Salted  Paper. 
Make  a  solution  as  follows  :  , 

Salting  Solution.    Formula  No.  1. 


Chloride  of  ammonium,  ....  100  grains. 

Distilled  water,   10  ounces. 

Formula  No.  2. 

Chloride  of  ammonium,  ....  100  grains. 

Distilled  water,   10  ounces. 

Gelatine,   10  grains. 

Formula  No.  3. 

Chloride  of  sodium,   40  grains. 

Chloride  of  ammonium,     ...  60  " 

Citrate  of  soda,   100  " 

Gelatine,   10  " 

Distilled  water,   10  ounces. 


Dissolve  the  gelatine  in  warm  water,  then  add  the  solution 
to  the  chloride  and  water,  and  filter  into  the  porcelain  or 
gutta-percha  dish.    The  mixture  in  each  formula  is  filtered 


MANIPULATION  OF  POSITIVE  PRINTING.  193 


before  use.  The  object  of  the  citrate  is  to  give  a  slight  i*osq 
tinge  to  the  middle  tones. 

The  sheets  of  paper  are  now  prepared  as  follows  : 
Fold  back  each  corner  of  the  sheet  so  as  to  form  a  lip  by 
which  to  hold  it ;  these  lips  are  from  the  smooth  or  satin 
side  backward  to  the  wrong  side.  Then  taking  the  lip  on 
the  right-hand  farther  corner  between  the  first  finger  and 
the  thumb  of  the  right  hand,  and  the  lip  on  the  left-hand 
corner  between  the  thumb  and  the  finger  of  the  left  hand, 
raise  the  sheet,  bend  it  into  a  curve,  and  lower  the  middle 
part  upon  the  surface  of  the  salting  solution ;  now  lower  the 
right  hand  gradually  so  that  the  farther  side  of  the  sheet 
rests  upon  the  fluid ;  and  then  lower  the  left  hand  in  like 
manner,  until  the  whole  sheet  swims  uniformly  upon  the 
surface.  The  next  thing  is  to  see  that  there  are  no  bubbles 
beneath  the  sheet.  With  a  glass  rod  in  the  right  hand  raise 
the  farthest  right-hand  corner  with  the  left  hand,  and  if  any 
bubble  becomes  visible  break  it  up  with  the  glass  and  moisten 
the  paper  where  the  bubble  existed,  and  proceed  in  this  man- 
ner with  one  half  of  the  sheet.  Next,  holding  the  glass  rod 
in  the  left  hand,  raise  the  nearest  left-hand  corner,  by  the 
lip,  with  the  right  hand,  and  remove  all  bubbles  from  the 
other  half.  When  these  are  all  broken  up,  and  the  paper  is 
moistened  on  the  parts  where  they  existed,  the  sheet  is  low 
ered  on  the  fluid  and  left  there  for  three  minutes.  The  opera 
tion  of  removing  the  bubbles  is  the  work  of  a  moment.  You 
have  to  learn  the  knack  of  floating  the  sheets  on  the  salting 
solution  without  soiling  the  back  of  the  sheet,  that  is,  with- 
out getting  any  of  the  fluid  on  this  side.  If  the  two  sidea 
of  the  paper  are  equally  smooth,  that  part  which  is  not  cov- 
ered with  the  salting  solution  is  marked  in  one  corner  with 
a  pencil  or  stamp-mark.  After  the  expiration  of  the  three 
minutes,  each  sheet  is  raised  in  the  following  manner.  The 
lips  will  have  sunk  down  on  the  surface  of  the  fluid  ;  with  the 
glass  rod  in  the  left  hand  raise  the  nearest  right-hand  cor- 
ner, seizing  this  lip  with  the  thumb  and  finger  of  the  right 
hand,  raise  the  sheet  gradually.  Laying  aside  the  rod,  seize 
now  the  nearest  left-hand  lip  with  the  left  hand  and  hold 
the  hands  apart  as  far  as  the  paper  will  permit,  and  the  left 
hand  more  elevated  than  the  right,  allow  the  sheet  to  drain 
into  the  bath.  Now  letting  the  right-hand  corner  go,  with 
a  pin  fix  the  upper  left-hand  corner  to  the  wooden  partition 
or  slip  of  wood  for  this  special  purpose.  If  the  sheets  are 
large,  pin  also  the  upper  right-hand  corner  in  like  manner, 
to  prevent  the  sheet  from  curling  upon  itself  whilst  drying. 


194 


MANIPULATION  OF  POSITIVE  PRINTING. 


Remove  the  accumulating  drops  of  salting  fluid  from  the 
lowest  corner,  and  then  let  the  sheets  dry.  After  this  opera- 
tion the  sheets  are  piled,  with  the  unsalted  sides  downward, 
one  upon  another,  and  a  smooth  board  placed  above  and  be- 
low the  pile,  and  submitted  to  pressure  until  required  for 
use. 

Preparation  of  Albumenized  Paper. 

Albumen  can  be  used  either  pure  or  diluted.  With  pure 
albumen  the  prints  are  very  brilliant,  but  the  paper  is  not  so 
easily  prepared.  Take,  for  instance,  the  whites  of  twenty 
eggs,  taking  care  to  separate  the  yolk  thoroughly,  and  place 
them  in  a  graduated  measure.  Remove  all  the  germs  with 
a  glass  rod,  and  ascertain  the  number  of  ounces.  Afterward 
pour  the  crude  albumen  into  a  clean  basin,  and  add  for  every 
ounce  ten  grains  of  chloride  of  ammonium  dissolved  in  the 
least  quantity  of  distilled  water.  Beat  the  mixture  into  a 
thick,  white  froth  by  means  of  an  egg-beater,  and  allow  it  to 
stand  for  ten  minutes  ;  then  remove  the  froth  with  a  fork, 
and  throw  it  upon  a  clean  hair-sieve.  Proceed  in  like  man- 
ner with  the  residual  fluid,  until  it  has  been  completely  con- 
verted into  froth  and  strained  through  the  sieve.  Now  leave 
the  albumen  to  stand  for  a  day  or  so,  well  covered  up  from 
dust ;  after  which  filter  through  a  piece  of  sponge,  and  again 
allow  the  mixture  to  settle  for  a  couple  of  days,  and  then 
pour  off  the  supernatant  liquid  portion  from  the  settlings 
into  the  porcelain  or  gutta-percha  dish  for  use. 

The  paper,  as  usual,  must  be  of  the  finest  quality,  and 
marked  or  stamped  on  the  back,  before  floating.  Much 
more  care  is  required  in  the  successful  management  of  laying 
the  paper  on  the  salted  albumen  than  upon  the  plain  salting 
solution,  for  bubbles  are  more  likely  to  be  formed,  and  are 
less  easily  removed  than  in  the  former  preparation.  Besides 
this,  if  the  paper  be  dry,  and  the  weather  also  very  dry,  the 
nlbumen  does  not  attach  itself  easily  to  the  paper,  and  in  this 
case,  although  a  sheet  has  been  thoroughly  floated,  and  with- 
out bubbles,  the  upper  part  of  the  sheet,  when  hung  up,  al- 
lows the  albumen  to  flow  off,  so  that  the  film  on  the  upper 
part  is  much  thinner  than  on  the  lower  part,  and  a  number 
of  irregular  marks  and  curves  are  apt  to  be  formed  on  the 
lower  part.  To  obviate  this,  the  sheet  is  suspended  by  its 
broadside,  by  which  the  distance  between  the  upper  and 
lower  side  is  the  least  possible.  The  time  of  salting  in  this 
bath  is  from  two  minutes  and  a  half  to  three  minutes.  Of 
course  in  all  cases  the  time  has  to  be  reckoned  from  the  mo- 


MANIPULATION  OP  POSITIVE  PRINTING.  195 


ment  the  sheet  lies  uniformly  and  without  bubbles  on  tho 
surface  of  the  solution. 

In  every  operation  of  this  nature  it  is  well  to  have  sys- 
tematic arrangements.  For  this  purpose  I  recommend  the 
photographer  to  proceed  as  follows  in  the  preparation  of  his 
drying-chamber.  On  the  side  of  the  room,  behind  the  salting 
solution,  and  at  an  elevation  of  the  eyes  of  the  individual, 
screw  on  a  slip  of  wood  a  couple  of  inches  wide  and  the 
length  of  the  room.  Supposing  then  the  sheets  are  twenty- 
two  inches  long,  then  bore  two  holes  twenty-one  inches  apart 
through  the  slip  of  wood ;  into  the  apertures  insert  corks,  fitting 
firmly,  and  projecting  about  half  an  inch  from  the  surface  of 
the  wood.  Into  the  center  of  each  of  these  corks  insert  the 
eye  end  of  a  steel  needle  inclined  slightly  upward.  The 
sheets  when  raised  by  the  two  interior  corners,  and  after 
draining,  are  hooked  by  the  two  upper  corners  upon  the  pro- 
jecting needles,  which,  before  their  insertion  into  the  corks, 
have  to  be  varnished  to  prevent  rusting  and  other  troubles. 
When  several  rows  of  sheets  have  to  be  dried  consenta 
neously  the  uppermost  slip  of  wood  must  be  the  thickest,  as, 
for  instance,  three  inches,  if  there  are  three  rows,  one  over 
the  other;  the  second,  two  inches ;  and  the  last,  one  inch  thick. 

In  proportion  as  the  albumen  accumulates  on  the  lower 
border,  it  is  removed  with  bibulous  paper,  until  the  papers 
finally  are  dry.  They  are  then  taken  down  and  planished 
between  rollers  or  otherwise,  and  piled  away. 

Preparation  of  Arrow-Root  Paper. 
Cut  out  a  board  a  trifle  less  in  length  and  width  than  the 
sheet  of  paper ;  fix  a  sheet  at  a  time  by  a  pin  at  each  cor- 
ner of  each  edge,  folding  the  edges  of  the  paper  down  over 
the  edges  of  the  board.  Then,  with  a  very  fine,  soft  and 
moist  sponge  cover  it  over  smoothly,  longitudinally  and  lat- 
erally with  the  following  salting  mixture : 

Formula. 

Chloride  of  sodium,  (common  salt,)        5  drachms. 

Citric  acid,  4  grains. 

Distilled  water,  19  ounces. 

Dissolve  and  filter.  Then  add  four  drachms  of  arrow-root, 
rubbed  with  cold  water  into  a  cream,  so  that  all  lumps  have 
been  thoroughly  broken  up  and  saturated.  Boil  the  mixture 
in  a  glass  or  porcelain  dish,  taking  care  to  stir  it  all  the 
while.  When  it  is  cold,  and  the  scum  has  been  removed,  it  is 
ready  for  application  with  the  sponge.  By  means  of  a  glass 
triangle  or  glass  rod,  all  ridges  or  asperities  may  be  removed, 


196 


MANIPULATION  OF  POSITIVE  PRINTING. 


and  the  paper  is  then  suspended,  as  before  directed  for  albu- 
men-paper. Arrow-root  paper  is  well  adapted  for  large  por- 
traits, and  even  for  large  landscapes ;  for  smaller  pictures, 
where  more  fineness  of  grain  and  sharpness  are  required,  al- 
bumenized  paper  is  by  far  the  best.  All  the  papers,  pre- 
pared as  directed,  will  keep,  but  they  are  best  when  fresh. 

Sensitizing  JBath. 
The  preparations  for  sensitizing  are  divided  into  two  class- 
es, one  containing  essentially  nitrate  of  silver,  ^nd  the  other 
ammonio-nitrate  of  silver;  these  are  subdivided  by  differ- 
ences in  the  strength.  The  ammonio-nitrate  of  silver  solu- 
tion is  certainly  much  more  sensitive  than  the  plain  silver 
bath ;  the  great  drawback  has  been  the  blackening  of  the  so- 
lution by  use,  for  which  several  remedies  have  been  proposed. 
Whichever  bath  is  used,  its  strength  has  to  be  maintained  at 
its  original  point  by  the  addition  of  fresh  silver  every  time  it 
is  used,  for  the  bath  soon  becomes  impoverished  by  the  float- 
ing of  paper  for  printing.  The  sensitizing  solution  must  al- 
ways be  slightly  acid,  in  order  that  the  whites  may  be  thor- 
oughly preserved. 

Formula  for  the  Plain  Silver  Solution. 

Nitrate  of  silver,  2  ounces. 

Rain-water,  12  ounces. 

Nitric  acid,  2  to  3  drops. 

The  paper  to  be  sensitized  in  this  bath  is  prepared  exactly 
in  the  same  manner  as  for  floating  in  the  salting  solution ; 
the  corners  are  turned  back,  and  then,  seizing  two  opposite 
corners  and  bending  the  paper  into  a  curve  with  the  middle 
and  salted  part  downward,  it  is  lowered  into  contact  with 
the  fluid,  while  first  one  end  is  gradually  let  down  and  then  the 
other,  taking  care  afterward  to  remove  all  bubbles  with  the 
glass  rod,  by  first  raising  one  corner  and  then  the  other. 
Previous  to  use,  the  bath  ought  to  be  always  filtered  from  in- 
numerable little  particles  and  scum  that  accumulate  on  its 
surface.  By  means  of  an  argentometer  the  strength  of  the 
bath  can  easily  be  maintained  at  a  given  point,  namely,  at 
about  70  grains  to  the  ounce  of  water ;  and  by  the  applica- 
tion of  test  paper,  it  can  be  ascertained  whether  it  be  acid  or 
alkaline,  and  thus  corrected.  I  will  repeat,  the  bath  must  be 
Slightly  acid. 

Filtered  every  time  it  is  used. 
Its  strength  maintained  at  20  grains  to  the  ounce. 
The  papers  are  floated  on  the  fluid  for  five  minutes,  then 


MANIPULATION  OF  POSITIVE  PRINTING. 


197 


raised,  allowed  to  drain,  and  hung  up  on  varnished  steel 
needles  inserted  into  corks  in  a  line  over  the  gutter  alluded 
to  in  a  former  part  of  this  work ;  or  if  such  a  contrivance  be 
wanting,  the  silver  solution  is  removed  from  the  pendent  cor- 
ners by  blotting-paper,  which  is  afterward  thrown  aside  on  a 
special  heap  for  reduction.  The  bath  by  use  will  become  discol- 
ored; in  such  a  case,  throw  in  a  small  quantity  of  solution  of 
common  salt  by  degrees  and  shake  well.  This  will  remedy 
the  evil  after  filtration,  but  it  removes  also  a  considerable 
quantity  of  silver,  which  has  to  be  replenished.  The  black 
residue,  together  with  the  precipitated  chloride  of  silver,  is 
preserved  with  all  other  refuse  silver  for  reduction. 

Formula  for  the  Ammonio- Nitrate  Silver  Solution, 


Dissolve  the  silver  in  six  ounces  of  water  ;  then  separate 
two  ounces  of  the  solution,  and  add  ammonia  to  it,  until  the 
precipitate  of  oxide  of  silver  first  formed  is  redissolved.  This 
solution  is  then  mixed  with  the  alcohol,  and  the  remaining 
silver  solution  and  water.  By  the  addition  of  ammonia  de- 
composition takes  place,  oxide  of  silver  of  a  brown  color  is 
thrown  down,  and  nitrate  of  ammonia  is  formed ;  an  addi- 
tional quantity  of  ammonia  then  dissolves  the  oxide,  so  that 
the  solution  contains  nitrate  of  ammonia  and  solution  ot 
oxide  of  silver  in  ammonia.  When  this  part  is  thrown  into 
the  remaining  solutions,  oxide  of  silver  is  again  precipitated ; 
the  final  solution  therefore  contains  free  oxide  of  silver,  and 
solution  of  oxide  of  silver  in  nitrate  of  ammonia  and  alcohol. 
The  alcohol  prevents  the  solution  of  the  albuminous  film  and 
discoloration  probably. 

The  papers  are  floated  in  this  bath  not  more  than  a  minute ; 
half  a  minute  I  find  in  most  cases  to  be  sufficient.  But  there 
is  this  caution  to  be  observed :  if  the  papers  when  removed 
from  the  bath  appear  streaked  with  oil,  it  is  well  to  rub  the 
fluid  gently  over  the  whole  surface  with  a  tuft  of  cotton  wool. 
The  bath  can  be  filtered,  but  in  that  case  the  same  filter  has 
to  be  used  over  and  over  again,  because  the  oxide  of  silver 
is  gradually  taken  up  and  dissolved  by  the  ammonia  liberated 
during  the  operation.  I  prefer,  however,  not  to  filter  the 
bath,  but  after  use  to  keep  it  in  the  stock-bottle,  together 
with  the  residue  of  oxide  of  silver.  When  about  to  use  it, 
it  is  carefully  decanted  into  the  dish,  and  after  settling,  a 
small  sheet  of  paper  is  drawn  over  the  surface  to  remove  any 


Nitrate  of  silver, 
Rain-water,  . 
Alcohol,     .  . 


2  ounces. 
8  ounces. 
1  ounce. 


198 


MANIPULATION  OF  POSITIVE  PRINTING. 


particles  that  might  be  left.  The  strength  of  this  bath,  like 
any  other,  has  to  be  kept  up  by  the  addition  of  crystals  of 
nitrate  of  silver  ;  fresh  alcohol  and  ammonia  are  added  from 
time  to  time.  The  albuminous  film  is  not  injured  by  this 
solution  ;  the  time  of  floating  is  much  shortened,  and  although 
the  strength  of  the  solution  is  higher  than  that  of  the  pre- 
ceding, no  more  silver  is  wasted  or  consumed  in  the  opera- 
tion, because  the  picture  is  maintained  on  the  surface  of  the 
film,  owing  either  -to  the  diminution  of  the  time  of  floating, 
or  to  the  induration  or  coagulation  of  the  albumen,  or  to  its 
dryness  and  consequent  impermeability  in  so  short  a  time. 

Fuminating  Process. 
The  advantages  of  the  ammonio-nitrate  sensitizing  solution 
are  attained  by  subjecting  the  sheets  of  paper,  already  sensi- 
tized by  the  plain-nitrate  of  silver  solution,  to  the  fumes  of 
ammonia.  The  modus  operandi  is  as  follows  :  Float  the  pa- 
pers for  four  or  five  minutes  in  the  first  bath,  containing  from 
sixty  to  seventy  grains  of  nitrate  of  silver  to  the  ounce  of 
water,  and  allow  them  to  dry  as  usual.  This  is  the  first  part 
of  the  process. 

Next  prepare  the  fuminating  box  or  chamber.  Where 
the  quantity  of  work  to  be  done  is  not  very  extensive,  a  box 
three  feet  long,  two  feet  wide  and  two  feet  deep  is  first  con- 
structed. On  either  side  and  five  inches  from  the  top  a  piece 
is  cut  out,  leaving  the  two  ends  projecting  five  inches  above 
the  two  sides.  Construct  next  on  either  side  a  shallow  box 
of  the  same  length  as  the  original  one,  five  inches  deep,  and 
two  feet  wide,  and  having  only  three  sides.  These  are  fast- 
ened by  screws  to  the  large  and  middle  box,  in  such  a  man- 
ner that  the  open  side  fits  exactly  where  the  piece  has  been 
cut  out,  forming  as  it  were  two  shelves.  By  means  of  trian- 
gular supports  these  shelves  are  held  in  a  firm  and  horizon- 
tal position,  and  give  an  appearance  to  the  box,  when  regarded 
from  the  end,  of  the  letter  T.  On  each  end  of  the  deep  box, 
as  well  as  on  each  side,  on  a  level  with  the  lateral  shelves, 
screw  on  four  narrow  slips  of  inch  stuff,  on  which  can  rest  a 
board  three  feet  long  and  two  feet  w^ide ;  this  board,  there- 
fore, in  its  place  covers  the  middle  box  like  a  lid.  When  it 
is  in  its  place,  screw  down  a  small  piece  of  wood  on  either 
end  of  one  side,  so  that  it  can  not  slide  too  far.  This  lid  has 
a  sliding  motion  by  means  of  an  iron  rod  in  the  middle  of  one 
side,  lying  horizontally,  and  passing  through  an  aperture  in 
the  side  of  one  of  the  shelves,  so  that  it  may  be  made  to  close 
the  top  of  the  box  or  open  it  when  required.    On  the  top  of 


MANIPULATION  OF  POSITIVE  PRINTING. 


199 


this  T-shaped  cavity,  there  are  three  doors,  each  three  feet 
long  and  one  foot  ten  inches  wide,  opening  by  hinges  as  fol- 
lows :  At  a  distance  of  one  foot  ten  inches  from  either  side  on 
the  top  of  this  cavity  screw  on  a  slip  of  wood  two  inches 
wide;  to  these  slips  the  hinges  are  all  fixed,  so  that  each 
lateral  door  opens  toward  the  middle,  and  lies  when  open 
upon  the  middle  door ;  whereas  the  middle  door  opens  to- 
ward one  side  and  lies  upon  the  side  door.  It  is  intended 
that  one  door  alone  is  to  be  opened  at  a  time.  The  wood  of 
which  these  doors  are  constructed  must  be  soft,  so  as  to  al- 
low the  insertion  of  small  tacks  or  pins.  This  is  the  fumin- 
ating  apparatus. 

The  sensitized  dried  sheets  or  pieces  of  paper  are  fixed 
upon  the  inside  of  each  door  by  sticking  a  pin  obliquely  into 
each  corner,  with  the  albumenized  surface  downward  when 
the  door  is  shut.  At  the  bottom  of  the  deep  box  place  a 
plate,  containing  a  drachm  or  more  of  ammonia.  In  winter  a 
pan  of  warm  sand  may  be  introduced,  with  the  plate  over 
this  in  order  to  increase  the  evaporation.  The  sliding  door 
all  this  while  is  open.  When  each  door  is  covered  with 
sheets,  or  with  as  many  as  are  required,  close  them.  It  is 
evident  that  the  fumes  of  the  ammonia  will  soon  fill  the 
whole  of  the  interior,  and  will  thus  come  in  contact  with  the 
surface  of  the  silvered  paper  and  produce  a  decomposition  of 
the  nitrate  of  silver  into  oxide  of  silver  and  nitrate  of  ammo- 
nia. After  the  paper  has  been  exposed  for  about  ten  min- 
utes, the  sliding  door  is  closed  by  pushing  it  forward  with 
the  iron  rod  until  it  juts  against  the  small  pieces  of  wood  on 
either  end  of  the  opposite  shelf.  ,  By  this  means  the  fumes 
of  ammonia  in  the  body  of  the  fuminator  are  excluded  from 
the  air,  and  only  that  portion  escapes  which  lies  on  the  shelves. 
The  fuminated  papers  are  then  taken  out  and  pinned  by  one 
corner  on  the  corks,  in  order  that  all  superfluous  ammonia 
may  escape,  when  they  will  be  ready  for  printing.  It  lias 
been  asserted  that  there  is  a  great  saving  of  silver  by  this 
process ;  that  the  film  is  much  more  sensitive  to  light,  and 
consequently  the  time  of  printing  is  shortened,  and  that  the 
tones  are  more  brilliant. 


CHAPTEE  XXXIL 

THE  PRINTING  OF  SENSITIZED  PAPER. 

The  operation  of  printing  is  performed  by  the  direct  rays 
of  the  sun  or  by  diffused  light.  Frames  of  various  sizes  are 
to  be  had  of  the  dealers  for  this  special  purpose.  These  are 
oblong  dishes,  about  two  inches  deep,  with  a  pane  of  plate 
glass  for  the  bottom,  lying  upon  a  ledge  loosely.  Upon  this 
the  negative  is  placed,  collodion  side  upward,  and  over  the 
negative  the  sensitized  paper,  albumen  side  downward.  A 
piece  of  chamois  leather,  soft  cloth  or  Canton  flannel  of  the 
size  of  the  pane  of  glass  is  placed  over  the  paper  carefully,  so 
as  to  keep  it  in  its  position  directly  over  the  negative,  and  to 
form  a  sort  of  cushion  when  the  folding  doors,  that  come 
next,  are  fixed  in  their  place.  There  is  quite  a  knack  in  ad- 
justing the  leather  so  as  not  to  produce  any  friction  upon  the 
negative,  which  would  certainly  injure  if  it  were  not  var- 
nished. The  negative  lies  as  near  the  middle  of  the  pres- 
sure frame  as  can  be,  and  in  the  same  direction  as  to  length. 
The  folding  doors  are  two  thin  flaps  of  wood  joined  by  hinges 
in  the  middle,  equal  in  size  together,  and  lying  horizontally 
to  the  pane  of  glass.  This  door  is  adjusted  in  its  place  over 
the  cloth  or  leather  in  the  following  manner.  Whilst  the 
outstretched  fingers  of  the  left  hand  are  holding  the  paper 
and  cloth  in  their  places,  without  the  slightest  friction,  the 
nearer  flap  is  put  in  its  place  and  held  down  by  a  gentle 
pressure,  whilst  the  left  hand  now  relinquishes  its  hold  and 
closes  down  the  other  flap.  By  means  of  strips  of  wood,  an 
inch  and  a  half  wide,  stretching  across  the  frame  and  fixed 
on  hinges  on  one  side  of  the  printing  frame,  and  supplied 
with  metallic  springs  beneath,  each  flap  is  pressed  down  and 
held  in  its  place  by  means  of  a  hook  on  the  other  side.  By 
such  an  arrangement  it  is  evident  that  each  folding  door  is 
independent  of  its  neighbor,  and  by  opening  it  the  cloth 
over  one  half  of  the  negative  can  be  thrown  back,  the  picture 
can  be  raised  and  examined,  and  again  replaced  without  dis- 
turbing the  relative  position  of  the  paper  and  negative.  So 


THE  PRINTING  OF  SENSITIZED  PAPER. 


201 


arranged,  the  printing  frame  is  now  exposed  to  the  sun,  by 
rearing  it  on  a  shelf  at  the  outside  of  the  window  right  in 
front  of  this  orb.  The  color  of  the  paper  will  soon  begin  to 
change,  and  soon  the  whole  picture  will  be  apparent.  Some 
negatives  produce  the  best  prints  when  exposed  to  a  very 
powerful  light ;  others  on  the  contrary  require  to  be  printed 
slowly.  A  negative  which  is  very  dense  will  yield  the  best 
effect  by  exposing  the  frame  to  diffused  light ;  whereas  a  very 
thin  negative  may  be  exposed  to  the  full  blaze  of  the  sun,  in 
order  to  be  printed  very  quickly.  The  best  prints  are  ob- 
tained from  negatives  that  are  neither  too  dense  nor  too  thin. 
The  frame  is  taken  into  a  shaded  corner  of  the  room  from 
time  to  time,  and  one  end  of  the  print  is  examined  in  order 
to  ascertain  the  progress  of  the  operation.  If  the  lights  are 
still  white,  and  the  shades  not  yet  bronzed  in  the  slightest 
degree,  the  print  is  not  yet  finished.  As  a  rule  it  may  be 
concluded  that  this  operation  is  complete  when  either  the 
lights  have  become  slightly  tinged  by  reduction,  or  when 
bronzing  is  beginning  to  appear  in  any  part  of  the  shadows. 
In  this  case,  take  in  the  frame,  and  placing  it  on  a  table  or 
shelf,  remove  the  folding  doors,  then  the  cloth,  and  finally 
the  print.  Be  careful  not  to  expose  the  print  to  a  strong 
light,  otherwise  the  whites  will  be  injured.  Place  it  between 
the  leaves  of  a  book  or  in  a  drawer  in  the  dark-room,  until  a 
sufficient  quantity  has  accumulated  for  the  next  operation. 
An  experienced  printer  will  be  able  to  obtain  satisfactory  re- 
sults as  far  as  circumstances  will  permit ;  but  it  is  utterly  im- 
possible to  force  an  inferior  negative  to  yield  a  superior  print ; 
a  certain  relation,  a  certain  happy  relation,  (a  remark  that  I 
have  so  many  times  repeated,  but  not  too  often,)  must  exist 
between  lights,  middle  tones  and  shades,  with  a  given  den- 
sity of  the  latter  in  order  to  secure  normal  prints  ;  and  where 
this  exists,  it  is  the  fault  of  the  printer  if  he  does  not  arrive 
at  the  maximum  result  of  perfection. 

Toning  of  the  Prints. 
In  the  dark-room,  illumined  by  the  yellow  light  of  a  lamp, 
or  by  that  which  passes  through  the  orange-yellow  non-ac- 
tinic glass,  examine  the  points  separately,  rejecting  each  in 
which  there  is  a  decided  failure,  and  cut  off  all  extraneous 
parts  that  are  certainly  not  required  when  mounted,  allow- 
ing, of  course,  always  sufficient  margin  for  the  final  trimming. 
Next  throw  each  print  separately  into  a  pail  or  tub  of  water, 
taking  care  that  its  surface  comes  in  contact  with  the  water, 
without  the  intervention  of  bubbles.    Keep  the  prints  in  mo- 


202 


THE  PRINTING  OF  SENSITIZED  PAPER. 


tion  by  turning  them  over  and  over  again  for  the  space  of 
five  minutes,  and  afterward  take  them  out  separately  and  im- 
merse them  in  another  tub  of  water  in  the  same  manner  as 
before.  The  water  from  the  first  pail  is  poured  into  a  large 
barrel  or  tank  kept  for  this  special  purpose.  Move  the  prints 
about  as  before  for  five  minutes,  and  then  proceed  to  the 
third  pail  in  like  manner.  The  wTater  from  the  three  pails  is 
poured  into  the  tank,  and  a  tea-spoonful  of  common  salt  is 
added  and  dissolved  by  agitation  with  a  wooden  stirrer ;  af- 
ter the  subsidence  of  the  deposit  of  chloride  of  silver,  the  ref- 
use water  is  allowed  to  flow  off  into  the  sink  by  a  stop-cock 
inserted  within  a  couple  of  inches  from  the  bottom  of  the 
tank. 

Formula  No  1.  For  the  Toning  Solution. 

Chloride  of  gold,  (pure,)  1  grain. 

Distilled  water,  8  ounces. 

Carbonate  of  soda  to  neutralize  the  acidity. 
Alcohol,  2  drachms. 

Formula  No.  2. 
Double  chloride  of  gold  and  potassium,  2  grains. 

Distilled  water,  3  ounces. 

Carbonate  of  soda,  3-5  grains. 

Formula  No.  3. 

Chloride  of  gold,  1  grain. 

Distilled  water,  8  ounces. 

Chalk  to  neutralize  the  acidity. 

Chlorinetted  lime,  5  grains. 

Alcohol,  2  drachms. 

Formula  No.  4.    Gold  and  TTranium. 

(  Chloride  of  gold,  (pure,)    ...    1  grain. 
No.  1.      •<  Distilled  water,   4  ounces.  ' 

(  Chalk  to  neutralize  the  acidity.  S    Filter  each 

(  Nitrate  of  uranium,      ....    1  grain.  )  and  then  mix. 
No.  2.      •<  Distilled  water,  4  ounces. 

(  Chalk  to  neutralize  the  acidity. 

Formula  No.  5. 

Chloride  of  gold,   .2  grains. 

Distilled  water,  8  ounces. 

Phosphate  of  soda,  100  grains. 

Neutralize  with  chalk. 

Formula  No.  6. 

'Chloride  of  gold,  (pure,)    .    .    2  grains. 

Distilled  water,   4  ounces. 

No.  1.     <  Carbonate  of  soda  to  neutralize  the  acidity, 
Phosphate  of  soda,  ....    2  grains. 

Acetate  of  soda,  2  grains. 

(  Nitrate  of  uranium,  ....    2  grains. 

No.  2.     <  Distilled  water,   4  ounces. 

(  Chalk  to  neutralize  the  acidity. 


Filter  the  latter 
and  mix. 


THE  PRINTING  OP  SENSITIZED  PAPER 


20S 


The  acidity  of  any  of  the  above  solutions  is  neutralized  as  fol 
lows  :  In  the  first  place  throw  into  the  solution  a  piece  of  blue 
litmus  paper  of  the  size  of  a  ten-cent  piece,  its  color  will  be 
turned  red ;  now  throw  in  either  carbonate  of  soda  or  carbc  n- 
ate  of  lime  until  the  blue  color  is  restored.  Carbonate  of 
lime  (chalk)  has  this  advantage  over  carbonate  of  soda,  it 
can  be  used  without  litmus  paper,  taking  care  only  to  throw 
in  a  superabundance,  which  does  no  harm,  and  can  afterward 
be  removed  by  filtration.  I  prefer  preparing  the  double  chlo- 
ride of  gold  and  calcium  beforehand,  and  in  quantity  in  a 
concentrated  liquid  form.  In  such  a  condition  a  few  drops 
can  be  added  to  the  toning  bath  in  a  moment,  whenever  it 
is  found  that  the  toning  does  not  commence  or  proceed 
satisfactorily. 

Pure  chloride  of  gold  is  a  deliquescent  salt,  is  not  easily 
crystallized,  and  when  crystallized  is  not  easily  retained  in 
this  form.  Its  color  is  of  a  deep  reddish  color.  But  the 
chloride  of  gold,  sold  as  such,  is  of  a  yellowish  color,  in  a 
dry  crystalline  condition,  and  is  not  deliquescent ;  it  is  there- 
fore not  pure  ;  it  is  probably  in  most  cases  a  double  chloride, 
either  of  gold  and  potassium,  or  of  gold  and  sodium.  These 
double  salts  are  used  in  toning,  as  recommended  in  the  above 
formulae  ;  but  it  must  be  remembered,  that  in  buying  such  an 
article,  double  the  quantity  will  be  required,  and  of  course 
you  have  to  pay  the  price  of  gold  for  the  soda  or  potassa  in 
the  mixture,  which  is  poor  economy. 

With  any  of  the  preceding  formulas  baths  may  be  formed 
which  will  produce  rich  tones.  Formula  No.  5  admits  the 
substitution  of  citrate  of  soda,  or  acetate  of  soda  for  the 
phosphate.  The  first  is  the  simplest,  and  I  think  the  most 
rational ;  probably  the  third  will  please  many ;  its  tone  is 
more  of  a  sepia.  The  aim  of  the  citrate,  acetate,  and  phos- 
phate is  to  produce  a  purple  tone.  The  uranium  bath  pro- 
duces a  rich  tone,  still  I  do  not  think  it  superior  to  the  sim- 
plest alkaline  gold  bath.  Use  the  bath  slightly  warm,  that 
is,  at  a  temperature  of  90°  or  100°.  Before  the  prints  are  in- 
troduced into  the  toning  bath,  pass  them  separately  through 
hot  water.  Let  the  bath  be  sufficiently  large  to  accommo- 
date a  number  of  prints  side  by  side ;  turn  them  over  contin- 
ually ;  keep  them  in  motion.  The  tone  of  the  prints  soon 
begins  to  change  ;  before  it  becomes  of  a  slate  blue,  take  each 
print  out,  wash  in  hot  water,  and  immerse  in  the  fixing  bath. 


Fixing  Solution. 


Hyposulphite  of  soda, 

Water,  

Alcohol,  .... 


2  ounces.  ) 
12  ounces.   >  Slightly  warm. 
4  drachms.  ) 


204 


THE  PRINTING  OF  SENSITIZED  PAPER. 


The  first  effect  of  the  toning  bath  is  to  change  the  color  to 
a  reddish  hue,  and  then  finally  back  again.  Move  the  prints 
about  in  this  bath  continually,  and  keep  them  in  until  the 
whites  are  perfectly  clear  when  viewed  by  transmitted  light, 
and  the  tone  has  been  restored.  Where  the  printing  has 
been  well  performed,  supposing  the  contrast  in  the  negative 
to  be  right,  the  color  of  the  deep  shades  is  but  very  little 
changed  in  the  fixing  solution,  and  very  soon  returns  to  the 
proper  tone.  If  the  whites  are  full  of  gray  spots  when  the 
prints  are  placed  between  the  light  and  the  eyes,  it  is  a  sign 
that  the  fixing  is  incomplete,  and  probably  too  that  the  prints 
during  the  washing  and  the  toning  have  been  too  much  ex- 
posed to  a  strong  light.  All  operations,  until  the  fixing  is 
complete,  ought  to  be  performed  in  a  room  lighted  by  non- 
actinic  rays.  When  the  tone  of  the  picture  and  the  transpar- 
ency of  the  whites  are  satisfactory,  remove  the  print  from 
the  fixing  bath  and  immerse  it  in  a  tub  of  water.  Do  so  with 
all  of  them,  until  the  fixing  operation  is  complete.  The  prints 
are  now  kept  in  motion  for  a  few  minutes  in  the  water,  in 
order  to  remove  as  much  as  possible  of  the  fixing  solution 
from  their  surface.  They  are  then  taken  out  and  allowed  to 
drain,  and  finally  immersed  in  another  tub  of  clean  water, 
where  they  remain  for  a  number  of  hours,  taking  care  to 
move  them  about,  and  to  turn  them  over  frequently.  The 
water  in  the  washing  operation  can  not  be  changed  too  fre- 
quently ;  in  fact,  it  is  by  far  the  most  desirable  plan  to  have  an 
arrangement  by  which  the  prints  can  be  subjected  to  a  run- 
ning stream  of  water,  which  can  easily  be  made  in  large  cities 
supplied  with  water  works. 

The  apparatus  for  this  purpose  is  adjusted  on  pivots  so  as 
to  rise  and  fall  like  the  beam  of  a  pair  of  scales,  and  it  is  put 
in  motion  by  the  weight  of  the  water  itself.  It  consists,  in 
the  first  place,  of  a  trough  of  wood  of  any  given  appropriate 
length,  as,  for  instance,  three  feet ;  its  breadth  may  be  one 
foot,  and  its  height  the  same.  It  is  divided  into  two  com- 
partments in  the  middle,  and  supported  on  pivots  in  the 
middle  of  the  base-board  about  six  inches  above  the  table  or 
shelf  on  which  it  rests ;  by  this  means  it  has  an  oscillating 
motion  or  play  of  about  twelve  inches  at  either  end,  like  a 
see-saw.  This  trough  is  placed  so  that  the  middle  division 
is,  when  horizontal,  immediately  below  the  stop-cock ;  but 
when  one  is  down  and  filled  with  water,  and  the  other  up 
and  empty,  it  is  evident  that  if  the  stop-cock  be  open,  the 
water  will  flow  into  the  empty  compartment  until  this  sinks, 
which  it  will  do  when  the  other  is  empty.    Each  compart- 


THE  PRINTING  OF  SENSITIZED  PAPER. 


205 


liient  is  supplied  with  a  syphon,  whose  arch  reaches  to  a  plane 
nearly  level  with  the  top  ;  the  calibre  of  this  syphon  is  some- 
what greater  than  that  of  the  ingress  pipe  furnished  with  the 
stop-cock.  Now  when  either  end  becomes  filled  with  water, 
the  latter  will  rise  higher  than  the  arch  of  the  syphon,  which 
will  then  be  filled  with  water.  The  longer  arm  of  the  syphon 
passes  through  the  end  of  each  compartment  and  discharges 
the  water  from  its  corresponding  end  quicker  than  the  water 
is  supplied  to  the  other  end  by  the  stop-cock.  By  this  expe- 
dient one  end  becomes  alternately  light  and  heavy,  and  thus 
produces  a  constant  oscillation  of  the  whole  trough  up  and 
down.  The  prints  to  be  washed  are  placed  in  these  troughs 
as  soon  as  they  leave  the  fixing  bath,  and  are  thus  kept  in 
motion  and  supplied  with  fresh  water  for  any  length  of  time. 
Such  a  machine  is  called  the 

Self-Acting  Photographic  Washing-Machine. 
When  prints  are  thus  treated  an  hour's  washing  will  re- 
move every  trace  of  the  hyposulphite  of  soda.  They  are 
then  taken  out  one  by  one  and  pinned  by  one  corner  to  slips 
of  wood,  or  suspended  on  varnished  hooks  inserted  into  corks, 
as  before  described  in  the  albumenizing  process. 

Mounting  of  Photographs. 
Photographs  may  be  cut  out  of  the  proper  size  and  shape 
either  before  they  are  starched  or  gummed  or  afterward. 
If  before,  the  following  is  the  mode  of  proceeding.  Place  a 
thick  plate  of  glass  before  you  on  the  table,  on  which  lay  the 
photograph,  picture  side  upward.  Next  place  over  this  a 
heavy  mat  in  such  a  position  as  to  present  the  best  appear- 
ance the  print  can  receive.  Holding  the  mat  firmly  in  its 
place,  by  means  of  the  first  and  second  finger  stretched  far 
apart,  with  a  sharp-pointed  penknife  cut  along  the  edge  of 
the  mat  through  the  paper  to  the  glass  all  the  distance  from 
the  end  of  the  second  finger  to  that  of  the  first.  If  you  stand 
to  perform  this  operation  (a  position  to  be  preferred  to  that 
of  sitting)  move  gently  round  to  the  left,  still  holding  the 
fingers  firmly  on  the  mat.  Press  upon  the  mat  with  the 
right  hand,  whilst  the  second  finger  advances  to  the  position 
of  the  first,  and  this  one  is  again  stretched  asunder  to  a  new 
point  along  the  edge  of  the  mat.  Now  make  another  in- 
cision along  the  edge  in  perfect  continuity  with  the  first,  and 
thus  proceed  to  the  termination.  This  act  of  cutting  out  the 
prints  requires' considerable  dexterity  in  pressing  the  plate, 
and  making  the  incision  so  that  the  terminal  cut  is  a  conti- 
nuity of  the  commencement,  and  that  the  edge  all  round  is 


206  THE  PRINTING  OF  SENSITIZED  PAPER. 


clean  and  not  dentated.  Where  the  business  is  extensive, 
it  is  advisable  to  fix  up  a  special  mounting-table  like  that, 
used  by  potters  for  the  formation  of  utensils  out  of  the  plas- 
tic clay.  Such  a  table  can  be  turned  by  the  feet  on  a  verti- 
cal pedestal,  allowing  the  operator  to  sit  all  the  time.  A 
whetstone  or  hone  is  a  very  necessary  appendage  to  the 
mounting-table. 

The  prints  are  now  turned  over  and  brushed  over  with  a 
strong  solution  of  gum-arabic,  a  mixture  of  gum-arabic  and 
gelatine,  or  what  is  still  better,  with  a  solution  of  patent 
starch  or  dextrine,  such  as  is  used  on  the  back  of  post-stamps. 
Where  a  number  of  photographs  are  mounted  upon  the  same 
paper,  it  is  usual  to  brush  them  over  on  the  back  with  the 
solution  before  they  are  cut  out,  and  when  dry  to  perform 
the  operation  just  described.  The  starched  surface  is  then 
made  moist  by  going  over  it  with  a  moist  sponge.  The  print 
is  now  adjusted  upon  an  appropriate  mount  and  pressed  ac- 
curately down  by  placing  first  a  sheet  of  clean  paper  over 
the  print,  so  that  its  edges  overlap  the  latter,  and  then  hold- 
ing the  first  and  second  finger  far  apart  and  firmly  on  its 
surface,  the  print  is  pressed  upon  the  cardboard  by  rubbing 
the  space  between  the  two  fingers  w^ith  a  burnishing  tool  or 
with  the  smooth  handle  of  a  tooth-brush.  The  fingers  then 
assume  different  positions,  and  the  burnishing  is  continued 
until  the  whole  print  is  smoothly  and  evenly  adherent  to  the 
mounts  beneath. 

Photographs,  after  they  have  been  starched,  or  moistened 
after  starching,  can  be  mounted  much  more  quickly  by  first 
adjusting  them  to  their  place  on  the  mounts,  and  then  pass- 
ing them  beneath  the  rollers  of  a  glazing  or  planishing  ma- 
chine. The  two  operations  are  then  performed  at  one  and 
the  same  time.  This  planishing  is  quite  an  improvement  to 
a  print;  it  is  altogether  superior  to  varnishing  or  glazing. 
The  best  rolling  machines  are  those  furnished  with  a  hori- 
zontal bed,  like  that  in  a  lithographic  press.  Still  those  that 
consist  simply  of  a  pair  of  rollers  are  very  efficacious  in  pro- 
ducing decided  improvements  in  stereographs  or  card-pic- 
tures. 

Great  care  is  required  in  keeping  out  all  particles  of  sand 
from  the  starch  or  gum,  for  where  these  appear  they  produce 
protuberances  on  the  photographs  or  apertures  when  the 
prints  are  submitted  to  pressure  in  the  rolling-machines.  It 
is  therefore  always  necessary  to  remove  them  from  the  starched 
surface  before  it  is  placed  on  the  cardboard,  wherever  such 
particles  are  discovered ;  and  to  obviate  the  repetition  of  such 


THE  PRINTING  OF  SENSITIZED  PAPER.  207 


troubles  or  dimmish  their  number,  it  becomes  the  duty  of  the 
operator  to  cover  his  gum  carefully  up  when  it  is  not  in  use. 

What  to  do  with  the  Clippings  of  Prints. 

Spoiled  prints,  soiled  sensitized  paper  and  the  cuttings  of 
pictures  may  as  well  be  preserved  as  not,  for  the  labor  con- 
sists simply  in  placing  them  in  some  corner  or  box,  instead 
of  throwing  them  away.  As  soon  as  the  stock  is  very  large, 
they  may  be  burnt  in  a  clean  stove  and  the  ashes  collected. 
These  ashes  contain  silver,  oxide  of  silver  and  other  combin- 
ations of  silver,  together  with  the  minerals  in  the  paper,  as, 
for  instance,  lime,  etc.  The  ashes  so  constituted  are  pressed 
closely  and  firmly  together  into  a  Hessian  crucible,  then  sub- 
mitted to  a  powerful  heat  and  thus  reduced.  Or  these  ashes 
may  be  mixed  with  the  chloride  of  silver,  obtained  by  preci- 
pitation of  old  baths  or  at  the  bottom  of  the  tanks  containing 
the  refuse  washing  water.  The  mass  is  first  well  dried,  then 
intimately  mixed  with  about  one  half  its  weight  of  either  car- 
bonate of  soda  or  potassa,  and  fused. 

In  large  establishments  the  refuse  silver  salts,  as  well  as 
Jie  cuttings  of  paper,  amount  to  quite  a  large  quantity  an- 
nually, and  are  sold  for  reduction  to  parties  who  make  it 
their  business.  Where  such  an  opportunity  presents  itself,  it 
is  more  advantageous  to  dispose  of  the  unreduced  refuse  than 
to  perform  the  operation  of  reduction  one's  self. 

Mounting  Stereographs. 
Stereoscopic  negatives  taken  from  nature  contain  two  pho- 
tographs, which,  when  printed,  are  inverted,  the  left  picture 
being  where  the  right  ought  to  be.  Some  photographers 
remedy  this  defect  by  cutting  the  negative  in  two  in  the 
middle,  and  then  proceeding  from  the  middle,  right  and  left, 
two  inches  and  three  quarters,  the  residual  slips  are  cut  off 
on  the  ends  and  thrown  aside.  The  two  negatives  are  now 
placed  upon  a  thin  glass  stereoscopic  slide,  perfectly  clean, 
and  side  by  side  in  juxtaposition,  but  inverted,  so  that  the 
right-side  negative  is  placed  on  the  left  side.  By  means  of 
gummed  or  glued  ribbon  on  the  upper  edges,  these  negatives 
are  held  firmly  on  the  slide  beneath.  The  negatives  being 
so  arranged,  the  prints  will  have  the  right  position,  and  re 
quire  only  to  be  pared  at  the  top  and  bottom  previous  to 
mounting.  For  this  purpose  a  piece  of  glass,  with  rectangular 
corners  and  ground  edges,  five  inches  long  and  two  inches  and 
a  half  wide,  is  placed  upon  the  prints  on  the  mounting-table 
or  slab  of  glass ;  with  a  sharp  penknife  go  round  the  edges, 
taking  care  to  press  the  glass  form  firmly  on  the  prints.  In 


208 


THE  PRINTING  OF  SENSITIZED  PAPER. 


this  way  the  pair  of  stereographs  will  be  cut  out  in  one  piece 
ready  for  gumming  and  mounting.  Copies  of  stereographs 
(if  taken  with  a  single  orthoscopic  lens)  do  not  require  the  ne- 
gative to  be  prepared  as  above  described ;  the  requisite  inver- 
sion exists  without  it. 

But  in  many  instances  the  negative  is  not  prepared  at  all 
in  this  manner  fbr  printing,  but  left  in  its  natural  or  unaltered 
condition.  In  this  case  (and  it  is  probably  the  easiest  method 
of  proceeding)  the  glass  form  is  laid  upon  the  inverted  print, 
and  the  combined  prints  are  cut  out;  after  which  another 
glass  form  of  exactly  half  the  size  is  laid  upon  one  end  of 
the  combined  prints,  which  are  then  cut  asunder.  The  larger 
glass  form  has  a  notch  on  the  top  and  bottom  edge  in  the  mid- 
dle ;  these  notches  are  placed  on  the  middle  line  of  the  print, 
and  serve  thus  to  direct  its  position.  If  this  middle  or  divid- 
ing line  between  the  two  prints  has  considerable  width,  which 
is  sometimes  the  case,  the  glass  form  must  be  in  proportion 
longer ;  but  the  smaller  form  retains  its  size  of  two  inches 
and  a  half.  Stereographs  of  groups  and  of  architectural  ob- 
jects are  frequently  cut  out  with  rounded  corners,  sometimes 
on  the  top  only,  and  sometimes  both  on  the  top  and  bottom. 
For  this  purpose  you  must  prepare  for  yourself  appropriate 
forms  of  glass,  by  grinding  down  the  corners  on  a  grind- 
stone, or  you  can  cut  out  the  requisite  shaped  mats  in  brass. 
Those  of  glass  are  by  far  the  easiest  to  construct. 

Mounts  for  stereographs  of  various  shades  of  color  can  be 
had  of  the  dealers  ;  these,  being  cut  by  machinery,  are  neater 
and  cheaper  than  those  you  can  make  yourself  from  cardboard. 
If  you  do  not  possess  the  power,  that  is,  have  not  cultivated 
the  faculty  of  seeing  stereoscopically  without  an  instrument, 
you  must  be  very  careful  not  to  invert  the  right  and  left  side 
pictures  between  the  cutting  and  mounting.  It  is  well  to  be 
provided  with  two  small  boxes,  one  marked  left  and  the  other 
right,  into  which  the  corresponding  prints  can  be  thrown  as 
soon  as  they  are  prepared  for  mounting.  The  mode  of  past- 
ing, adjusting  to  position,  and  passing  beneath  the  roller  is 
the  same  with  the  stereograph  as  that  with  the  ordinary  pho- 
tograph, which  has  been  already  described. 


CHAPTER  XXXIII. 


bertrand's  new  process  for  positive  printing. 

Saxony  paper  is  the  best  for  this  process  ;  the  equality  of 
the  mass  is  not  absolutely  necessary,  but  that  which  contains 
iron  stains  must  be  rejected. 

The  first  preparation  of  the  paper  is  to  impregnate  it  with 
a  soluble  chloride ;  this  is  effected  by  plunging  it  into  the 
following  bath  : 

Alcohol,  spec,  grav.,  .842,   .    .    .    100  parts. 

Benzoin,  10  " 

Chloride  of  cadmium,    ......     5  " 

The  paper  may  be  floated  on  the  surface  or  completely  im- 
mersed. The  most  expeditious  means  is  to  take  a  dozen 
sheets  and  immerse  them  one  by  one  in  the  bath,  by  means 
of  a  glass  triangle ;  when  a  certain  quantity  has  been  im- 
mersed, they  are  all  turned  over  at  once,  and  then  taken  out 
one  at  a  time  and  hung  up  to  dry ;  take  care  to  place  a  piece 
of  blotting-paper  in  contact  with  the  lowest  corner  of  each, 
in  order  to  produce  an  accumulation  of  fluid  in  this  place. 

The  sheets  dry  very  quickly ;  a  few  minutes  are  sufficient. 
If  necessary,  they  may  be  dried  by  artificial  heat. 

The  advantage  accruing  from  the  use  of  benzoin  is  to  fill 
up  completely  all  the  pores  of  the  paper ;  air  and  moisture 
can  no  longer  penetrate  into  the  interior  of  the  print,  which 
*s  thus  protected  against  the  greatest,  if  not  the  only  cause 
of  deterioration.  Besides  this,  benzoin  communicates  to  pa- 
per the  gloss  of  albumen,  but  in  a  less  degree. 

The  chloridized  paper  will  keep  a  long  time ;  in  order  to 
sensitize  it,  place  it  in  contact  with  the  following  bath : 

Water,  100  parts. 

Nitrate  of  silver,  15  parts. 

exactly  as  for  albumen-paper. 
If  it  be  required  to  keep  the  sensitized  paper  for  some  time, 


210 


bertrand's  new  process. 


it  may  be  placed  in  one  of  Marion's*  boxes,  where  it  will 
keep  perfectly. 

.  The  exposure  beneath  the  negative  is  much  shorter  than 
for  albumen-paper ;  the  picture  may  be  printed  deeper  than 
required  at  the  end  after  fixing.  If  the  time  has  been  too 
long,  the  blacks  become  deep  green,  but  there  is  no  necessity 
for  anxiety  about  the  matter,  the  toning  bath  will  restore 
them  to  their  original  black. 

The  prints  may  be  toned  either  in  the  Bayard  bath : 

Water,   1000  parts. 

Chloride  of  gold,   1  pari 

Chloride  of  ammonium,  ....  20  parts. 
Hyposulphite  of  soda,   4  parts. 

or  in  the  acetate  bath : 

Water,   1000  parts. 

Chloride  of  gold,   1  part. 

Acetate  of  soda,   30  parts. 

Glover* s  Pesinized  Printing  Process. 
Salting  Solution. 

Gum  thus,  180  grains. 

Gum  mastic,   40  grains. 

Chloride  of  zinc,   200  grains. 

Alcohol,  8  fluid  ounces. 

Sulphuric  ether,   2  ounces. 

The  object  of  adding  the  ether  is  to  insure  the  speedy  so- 
lution of  the  mastic.  The  paper  is  to  be  immersed  in  the 
above  for  five  minutes,  covering  the  dish  with  a  sheet  of 
glass  to  check  evaporation.  Take  out,  drain  closely,  and 
dry  before  the  fire.  Too  much  stress  can  not  be  laid  upon 
the  necessity  of  perfect  dryness,  so  that  if  the  salted  paper  be 
put  away  for  future  use,  it  must  again  be  held  some  time  be- 
fore the  fire,  previous  to  floating  on  the  silver  bath,  or  it  will 
not  take  up  the  solution  evenly.  The  silver  bath  is  composed 
as  follows  : 

Alcohol,  spec,  grav.,  .805,  ...     4  ounces."] 

Gum  thus,   80  grains,  y  Dissolve. 

Gum  mastic,  10  grains.  J 

Nitrate  of  silver,   960  grains.  ) 

Distilled  water,   4  ounces.  J 

Mix  the  two  solutions  ;  shake  up  well ;  filter,  and  add  four 

*  This  box  is  oblong  or  square,  and  constructed  of  zinc,  with  a  tight-fit- 
ting cover.  At  the  bottom  there  is  a  plate  for  containing  fused  chloride  of 
calcium,  above  this  a  shelf  of  wire-gauze,  on  which  the  sensitized  sheets  are 
placed.  When  the  lid  is  accurately  closed,  whatever  moisture  may  be  in  the 
box,  it  will  be  absorbed  by  the  chloride,  which  is  a  very  deliquescent  salt. 


bertkand's  new  process. 


211 


drops  of  nitric  acid.  When  the  paper  has  been  in  contact 
with  the  above  solution  a  few  seconds,  it  has  a  tendency  to 
curl  up,  which  must  be  checked  by  breathing  upon  the  edges. 
After  it  has  settled  flat  on  the  surface,  allow  it  to  remain  ten 
seconds ;  it  is  then  ready  to  be  removed.  Take  hold  of  the 
sheet  by  one  corner,  and  stroke  it  with  a  glass  rod,  kept  for 
this  purpose  alone,  to  remove  the  surplus  solution,  and  dry  be- 
fore the  fire.  It  is  then  ready  for  fuming  over  a  dish  of  am- 
monia. This  last  operation  reduces  the  exposure  in  the 
printing  frame  about  one  third,  besides  insuring  success  in 
toning,  under  almost  every  condition  of  the  coloring  bath. 

On  removal  from  the  printing  frame,  wash  in  tepid  water, 
and  tone  by  any  of  the  alkaline  processes.  That  which  an- 
swers best  in  my  hands  is  composed  of  acetate  of  soda,  pre- 
pared at  least  twenty-four  hours  before  use,  with  the  addition 
of  a  few  drops  of  the  usual  solution  of  chloride  of  gold  im-  , 
mediately  before  immersing  the  prints. 

Fix  in  a  nearly  saturated  solution  of  hyposulphite  of  soda, 
containing  five  per  cent  of  alcohol. 

The  subsequent  thorough  washing  must  not  be  neglected 
in  this  or  any  other  printing  process. 

Or  in  any  other  bath. 

The  print  soon  assumes  a  black  tone,  which  is  difficult  to 
obtain  with  albumen. 
It  is  finally  fixed  in 

Water,  100  parts. 

Hyposulphite  of  soda,  20  parts. 

As  soon  as  the  print  is  well  washed,  it  is  left  to  dry,  and 
afterward  brushed  over  with  a  piece  of  flannel,  or  a  pad  of 
cotton,  in  order  to  give  it  a  gloss.  It  is  evident  that  var- 
nishing is  useless. 

11 


CHAPTER  XXXIV. 


PRINTING  BY  DEVELOPMENT. 

During  the  feeble  light  of  winter  in  high  northern  or 
southern  latitudes,  as  also  in  the  preparation  of  enlarged 
views  or  portraits  with  the  solar  camera,  printing  by  devel- 
opment is  of  very  great  utility.  It  is  quite  analogous  to  the 
operation  of  producing  a  collodion  picture  by  the  agency 
of  a  reducer ;  and  the  same  materials  in  general  are  em- 
ployed in  the  two  branches. 

Formula  for  the  Salting  Solution. 
JSFo.  1.    With  the  Chlorides. 
Chloride  of  sodium,  (common  salt,)    .    .    .  100  grains. 

Hydrochloric  acid,     .    ,   6  drops. 

Rain-water,  12  ounces. 

Immerse  the  papers  in  this  mixture  and  let  them  remain  in 
it  for  two  or  three  hours,  then  take  them  out  and  allow  them 
to  dry. 

Formula  for  Sensitizing  Solution. 

Nitrate  of  silver,  1  ounce. 

Citric  acid,  8  grains. 

Distilled  or  rain-water,  8  ounces. 

Float  the  papers  on  this  solution  for  three  minutes,  and  then 
suspend  them  on  the  varnished  needles,  or  on  a  cord  with 
clothes-pins.  Remove  all  the  fluid  that  accumulates  on  the 
lower  side,  or  on  the  corners.  As  soon  as  the  papers  are 
moderately  dry  they  may  be  exposed  beneath  the  negative 
or  on  the  screen  of  the  solar  camera  until  a  faint  image  ap- 
pears. Beneath  a  negative  in  the  rays  of  the  sun,  the  time 
of  exposure  will  not  exceed  three  or  four  seconds ;  in  feeble 
light  a  minute  or  more  may  be  required.  As  soon  as  the 
print  is  sufficiently  distinct,  it  is  withdrawn  and  laid  upon  a 
piece  of  glass  somewhat  smaller  in  dimensions  than  the  pa- 
per, picture  side  upward ;  two  opposite  edges  of  the  paper 
are  folded  beneath  the  glass,  and  in  this  position  the  paper 
and  the  glass  together  are  placed  on  the  left  side  of  a  capa- 
cious gutta-percha  developing  dish. 


PRINTING  BY  DEVELOPMENT. 


213 


Formula  for  Developing  Solution. 

Pyrogallic  acid,  12  grains. 

Citric  acid,  6  grains. 

Water,  6  ounces. 

Of  this  solution  take  sufficient  to  cover  the  paper.  Inclining 
the  dish  downward  to  the  right  side,  pour  in  the  solution  ; 
then  dexterously  raising  the  right  side,  the  fluid  will  flow  or 
may  be  made  to  flow  over  the  whole  surface  without  pro- 
ducing any  lines  of  stoppage.  This  is  very  important,  be- 
cause any  stoppage  on  such  paper  would  be  as  injurious  as 
on  collodion  prints.  The  development  commences  and  pro- 
ceeds as  rapidly  as  on  a  collodion  negative,  and  requires  just 
the  same  amount  of  vigilance.  As  soon  as  the  proper  con- 
trast has  been  attained,  the  further  reduction  is  caused  to 
cease  by  pouring  off  the  developer  into  the  sink  or  waste- 
tub,  and  then  by  washing  at  the  tap.  The  washing  must  be 
performed  with  care  and  effectually.  After  this  operation 
the  prints  are  fixed  in  the  following  solution : 

Formula  for  the  Fixing  Solution. 

Hyposulphite  of  soda,  1  ounce. 

Water,  16  ounces. 

The  prints  are  kept  in  this  solution  until  the  whites  are  per- 
fectly clear,  which  will  require  from  ten  minutes  to  half  an 
hour.  They  are  then  taken  out  and  submitted  to  the  regu- 
lar process  of  washing,  in  order  to  remove  every  trace  of 
the  hyposulphites. 

Second  Method  with  a  Chloride  and  a  Bromide. 
Formula  for  Salting  the  Paper. 


White  of  egg,   10  ounces. 

Distilled  water,   15  ounces. 

Chloride  of  sodium,   1  drachm. 

Bromide  of  potassium,   1  drachm. 


Dissolve  the  salts  in  the  water  and  add  the  solution  to  the 
albumen,  which  has  to  be  beaten  up  into  a  froth  and  allowed 
to  subside  several  hours  in  a  cool  place.  The  clear  super- 
natant liquid  is  decanted  carefully  or  filtered  from  the  de- 
posit into  the  appropriate  dish  for  salting  operations. 

The  papers  are  floated  in  the  ordinary  way  on  the  surface 
of  this  bath  for  three  minutes,  and  then  hung  up  to  dry  on 
cords  and  attached  by  means  of  clean  clothes-pins.  After 
this  operation  the  papers  are  put  in  a  long  tin  box  which  is 
inserted  in  a  deep  kettle  of  boiling  water,  taking  care  that 
none  of  the  water  can  get  access  to  the  paper,  but  that  the 


214 


PRINTING  BY  DEVELOPMENT. 


paper  is  submitted  through  its  whole  length  to  the  heat  of 
steam  ;  the  operation  is  still  more  effectual  if  hot  steam  could 
come  in  contact  with  the  albumenized  surface  ;  such  an  ex- 
pedient is  intended  to  coagulate  the  albumen.  The  omission 
of  this  part  of  the  operation  must  not  deter  the  operator 
from  trying  the  process  ;  the  results  will  not  materially  be 
changed,  because  the  coagulation  can  be  effected  in  the  sen- 
sitizing bath. 

Formula  for  the  Sensitizing  Solution. 

Nitrate  of  silver,  1  ounce. 

Distilled  water,  12  ounces. 

Citric  acid,  3  drachms. 

Alcohol,  1  ounce. 

The  papers  are  floated  on  this  bath  from  two  to  three  min- 
utes, and  are  then  allowed  to  dry  as  usual.  An  exposure  of 
from  eight  to  ten  seconds  in  the  full  sun  will  be  sufficient ; 
whilst  as  many  minutes  will  be  required  in  a  weak  light. 
The  picture  must  be  quite  visible,  or  very  nearly  so,  before 
it  can  be  said  that  the  exposure  is  long  enough. 

Developing  Solution. 

Gallic  acid,  6  grains. 

Distilled  water,  2  ounces. 

The  operation  of  development  is  best  performed  in  a  glass 
or  gutta-percha  dish ;  the  print  is  first  moistened  and  then 
placed  on  the  bottom  of  the  vessel  to  which  it  adheres.  The 
developing  fluid,  being  poured  on  the  inclined  right-hand 
side,  is  flowed  over  the  print  almost  instantaneously  ;  if  any 
part  remains  not  covered,  a  slight,  quick  motion  will  easily 
bring  the  fluid  over  the  part,  or  a  glass  triangle  will  cause 
the  difficulty  to  disappear,  dragging  along  with  it  sufficient 
of  the  fluid  to  cover  the  part  denuded.  The  reduction  is 
very  rapid ;  and  where  the  exposure  has  been  about  right, 
the  development  of  the  image  will  be  complete  in  two  or  three 
minutes.  In  very  cold  weather  it  is  better  either  to  use  a 
stronger  bath  or  to  warm  the  bath  by  floating  it  in  warm 
water.  Gallic  acid  in  solution  is  very  apt  to  become  mouldy 
by  keeping,  and,  consequently,  a  small  piece  of  camphor,  or 
a  drop  of  oil  of  cloves,  is  mixed  with  the  bath  to  prevent  this 
sort  of  decomposition.  An  under-exposed  picture  develops 
very  slowly,  and  by  a  long  continuance  of  the  action  of  the 
acid  it  becomes  uniformly  dark-colored  without  any  grada- 
tion of  tone  ;  on  the  contrary,  an  over-exposed  picture  is 
developed  with  great  rapidity,  and  has  to  be  removed  from 
the  bath  quickly  to  prevent  its  assuming  a  dark  color  over 


PRINTING  BY  DEVELOPMENT. 


215 


the  whites.  If  printed  deep  enough  in  the  shades,  in  such  a 
case,  the  lights  would  in  the  mean  while  be  completely 
spoiled.  The  best  prints  are  those  in  which  the  gradation 
is  all  thoroughly  and  rather  slowly  brought  out  in  the  print- 
ing ;  these  are  afterward  carefully  washed  and  fixed  in  a 
weak  solution  of  hyposulphite  of  soda,  containing  as  follows : 

Hyposulphite  of  soda,  1  ounce. 

Water,  20  ounces. 

The  prints  remain  in  this  solution  for  a  quarter  of  an  hour 
or  so,  and  are  again  thoroughly  washed.  After  this  proceed 
ing,  if  the  tones  are  not  satisfactory,  the  prints  may  be  im- 
mersed in  the  gold  toning-bath,  in  order  to  receive  a  gold 
deposit,  which  modifies  the  color.  Any  of  the  gold-toning 
formulas  given  will  answer  the  purpose.  If,  in  the  opera- 
tion of  developing,  etc.,  the  whites  are  not  clear,  an  improve- 
ment in  this  respect  is  effected  by  immersing  the  well- washed 
prints  in  a  bath  containing  one  ounce  of  chlorinetted  lime  to 
ten  ounces  of  water. 

Third  Method  with  an  Iodide. 
Formula  for  Salting  Solution. 


i Nitrate  of  silver,     ........  44  grains. 

Distilled  water,  2  ounces. 

{Iodide  of  potassium,  7  drachms. 
Distilled  water,  2  ounces. 


Dissolve  the  two  salts,  and  then  mix  the  solutions  together, 
which  will  produce  a  precipitate  of  the  yellow  iodide  of 
silver.  Add  to  this  a  concentrated  solution  of  iodide  of 
potassium,  until  the  precipitate  is  dissolved.  The  fluid  is 
then  ready  for  the  bath. 

Float  the  papers  on  this  bath  in  the  usual  manner  for 
about  three  minutes,  or  until  they  lie  flat  on  the  solution. 
They  are  then  taken  out  and  hung  up  to  dry.  After  this 
proceeding  they  are  floated  in  a  quantity  of  rain-water,  two 
and  two  together  and  back  to  back,  for  a  number  of  hours, 
taking  care  to  turn  them  over  from  time  to  time.  The  sur- 
face thus  prepared  assumes  a  very  uniform  but  pale  yellow 
color.    The  papers  are  again  taken  out  and  hung  up  to  dry. 

Sensitizing  Bath.  Formula. 

Distilled  water,  25  ounces. 

Aceto-nitrate  of  silver  solution,   ....     4  drachms. 

The  solution  of  aceto-nitrate  of  silver  is  prepared  as  fol- 
lows 


216 


PRINTING  BY  DEVELOPMENT. 


Nitrate  of  silver, 
Acetic  acid,  .  , 
Distilled  water, 


1  ounce. 

2  ounces. 
10  ounces. 


Or  the  complete  formula  may  stand  as  follows,  where  oper- 
ators do  not  wish  to  keep  a  stock  of  the  aceto-nitrate  of 
silver : 


The  papers  are  floated  on  this  bath  for  three  minutes,  and 
Jien  taken  out  and  hung  up  to  dry.  Whilst  the  surface  is 
still  somewhat  moist,  they  are  exposed  beneath  a  varnished 
negative,  or  on  the  screen  of  the  solar  camera,  for  a  few 
seconds.  The  image  in  this  case  is  quite  latent.  In  dull 
weather,  and  when  the  light  is  very  feeble,  half  a  minute's  ex- 
posure will  suffice.  The  print  is  developed  by  pouring  upon 
it,  in  the  manner  already  indicated,  a  saturated  solution  of 
gallic  acid  containing  about  one  third  its  quantity  of  aceto- 
nitrate  of  silver.  If  the  development  is  very  slow,  the  ex- 
posure has  been  too  short ;  on  the  contrary,  the  develop- 
ment is  quite  rapid  when  the  exposure  has  been  too  long. 
As  soon  as  the  print  is  completely  brought  out  in  all  its  de- 
tails, it  is  immersed  in  water  and  very  thoroughly  washed 
in  order  to  remove  every  trace  of  gallic  acid. 

The  prints  are  then  immersed  in  a  solution  of  hyposulphite 
of  soda  as  follows : 

Hyposulphite  of  soda,  2  ounces. 

Water,  10  ounces. 


The  prints  do  not  change  much  by  immersion  in  the  fix- 
ing solution,  if  the  time  of  exposure  has  been  sufficiently  pro- 
longed ;  if  the  time  has  been  too  short,  the  dark  color  will  be- 
come pale  and  red.  If  the  tones  of  the  shades  do  not  assume 
a  dark  color  in  the  developing  solution,  the  cause  may  be 
attributed  to  the  want  of  aceto-nitrate  of  silver  in  the  gallic 
acid;  and,  as  a  rule  to  be  observed,  the  aceto-nitrate  is 
gradually  added  where  the  development  or  the  intensity 
relax.  If  the  toning  in  the  fixing  solution  becomes  inky,  the 
gold  may  be  omitted. 

Method  of  Sensitizing  by  Means  of  Nitrate  of  Uranium. 
( The  Process  of  JSfiepce  de  Saint  Victor.) 
The  paper  used  in  this  operation  has  to  be  kept  in  the 
dark-room,  or  at  least  excluded  from  light,  for  several  days 
previous  to  its  employment.  It  is  then  floated,  without  any 
other  preparation,  on  the  following  bath  : 


Distilled  water, 
Nitrate  of  silver, 
Acetic  acid,  . 


25  ounces. 
18  grains. 
2  scruples. 


Chloride  of  gold, 


2  grains. 


PRINTING  BY  DEVELOPMENT. 


Sensitizing  Bath* 

Nitrate  of  uranium,  1  ounce. 

Distilled  water,  5  ounces. 

After  two  or  three  minutes  the  papers  are  removed  from 
the  bath,  allowed  to  drain,  and  then  hung  up  and  dried. 
They  will  keep  a  long  time  when  not  exposed  to  light.  The 
time  of  exposure  beneath  a  negative  varies  with  the  intensi 
ty  of  the  light ;  from  one  to  ten  minutes  in  the  sun,  and  from 
a  quarter  of  an  hour  to  an  hour  in  a  feeble  diffused  light. 
The  image  is  barely  visible. 

Developing  Solution.    JVo.  1. 

Nitrate  of  silver,  1  drachm. 

Acetic  acid,  1  to  2  drops. 

Distilled  water,  2  ounces. 

The  development  is  very  rapid.  Almost  as  soon  as  the 
print  is  immersed  in  the  fluid,  the  picture  comes  out  and 
proceeds  to  its  termination  with  great  velocity.  As  soon  as  ' 
the  development  has  advanced  far  enough,  the  prints  are 
plunged  into  water,  and  thus  washed  and  fixed  at  the  same 
time. 

Developing  Solution.    JSTo.  2. 

Chloride  of  gold,  10  grains. 

Hydrochloric  acid,  1  drop. 

Distilled  water,  12  ounces. 

Prints  are  developed  in  this  bath  with  more  rapidity  than 
in  the  preceding. 

Another  Method. 
Sensitizing  JBath. 

Nitrate  of  uranium,  1  ounce. 

Distilled  water,  10  ounces. 

Developing  Solution. 

Bichloride  of  mercury,  5  grains. 

Distilled  water,  12  ounces. 

Pass  the  prints  through  this  solution,  and  then  wash  them 
very  carefully,  after  which  they  are  immersed  in  the  follow- 
ing bath : 

Nitrate  of  silver,  2  drachms. 

Distilled  water,  12  ounces. 

When  the  image  is  intense  enough,  wash  the  prints  thor- 
oughly and  hang  them  up  to  drv„ 


CHAPTEE  XXXV. 


THE  CARD-PICTURE. 

This  picture  does  not  differ  from  any  other  photograph  in 
the  essential  parts  of  its  structure  or  preparation.  No  pic- 
ture has  ever  had  so  wide  a  sphere  of  action,  has  gratified 
taste  so  long,  or  has  been  as  productive  of  gain  to  the  pho- 
tographer as  the  card-picture.  It  is  the  picture  of  the  day, 
and  has  tended  considerably  to  simplify  the  photographic  es- 
tablishment. A  few  years  past  a  number  of  cameras  were 
required,  ranging  from  the  quarter  to  the  extra  four  fourth 
tube  ;  now,  a  single  tube,  either  a  one  fourth  or  a  one  third 
will  be  a  complete  outfit  as  regards  lenses  for  an  ordinary 
practitioner,  with  which,  Deo  volente,  and  the  war  to  boot,  a 
fortune  may  soon  be  realized.  The  card-picture  generally 
comprehends  the  whole  figure,  either  sitting,  standing,  grace- 
fully leaning  against  a  pillar  or  balustrade,  performing  some 
natural  and  easy  operation,  as  playing  the  piano  or  guitar, 
trimming  a  flower  in  the  arbor,  or  sailing  in  the  yacht ;  in  fact, 
the  photographer,  at  least  the  artist,  aims  to  pose  his  model 
in  the  midst  of  nature's  charms  with  ease  and  grace,  and  per- 
fectly free  from  all  constraint. 

The  size  of  the  card-picture  is  a  distinct  characteristic  from 
all  other  pictures.  The  mounts  of  cardboard  for  this  picture 
are  four  inches  long  by  two  inches  and  one  third  wide  ;  they 
can  be  had  already  prepared,  plain  or  ornamented,  with  gilt 
edges,  or  with  a  gilt  border,  at  any  of  the  photographic 
wholesale  establishments  in  the  city.  The  prints  are  smaller 
than  the  mounts,  leaving  a  margin  of  about  one  tenth  of  an 
inch  on  either  side  and  on  the  top  ;  the  margin  at  the  bottom 
is  larger,  being  about  a  quarter  of  an  inch.  The  paper  on 
which  such  pictures  are  printed  is  of  the  finest  quality,  and 
very  uniformly  and  highly  albumenized.  It  is  impossible  to 
obtain  the  fine,  sharp  definition  on  plain  paper  as  on  albu- 
men, because  of  the  difference  of  homogeneity  in  the  two 
surfaces.  Tinted  albumen  paper,  too,  is  now  sometimes  used 
to  meet  the  wishes  of  the  fanciful,  or  the  cravings  after  novelty. 


THE  CARD-PICTURE. 


219 


Lenses  for  the  Card-Picture. 
Lenses  for  the  card-picture  are  prepared  with  great  care, 
so  as  to  produce  as  little  distortion  as  possible  in  the  com- 
plete figure.  On  this  account  a  long-focussed  tube  is  prefer- 
red to  one  that  is  shorter  ;  but  of  two  tubes,  if  they  both  pro- 
duce irreproachable  pictures  in  a  given  room,  the  one,  which 
is  the  result  of  the  short-focussed  instrument,  will  exhibit 
more  roundness,  a  finer  stereoscopic  effect  than  the  other. 
Choose  therefore  the  shortest  tube  that  will  perform  all  that 
is  required  in  a  card-picture,  and  at  the  distance  which  your 
glass-house  will  admit  of.  Where  the  business  in  this  depart- 
ment is  extensive,  two  tubes,  or  even  four  tubes  are  mounted  at 
the  requisite  distance  apart  for  the  taking  of  two  or  four  photo- 
graphs at  the  same  time.  Furthermore,  by  an  arrangement 
of  the  plate-holder  in  the  camera,  by  which  it  is  caused  to 
slide  either  horizontally  or  vertically,  or  in  both  directions, 
as  many  as  eight  or  sixteen  photographs  can  be  taken  at  the 
same  sitting.  It  would  be  a  waste  of  time  to  get  up  such 
cameras  one's  self ;  they  are  manufactured  very  neatly  and 
accurately  by  city  artisans,  and  are  fitted  up  with  the  num- 
ber of  tubes  ordered  or  required.  Each  tube  is  focussed  se- 
parately upon  the  sitter,  and  then  by  a  shutter  the  tubes  are 
opened  and  shut  cosentaneously  at  will.  After  a  proper 
number  of  seconds  have  expired,  the  shutter  is  closed,  and 
the  plate-holder  is  moved  a  fixed  distance,  so  as  to  expose 
another  portion  of  the  collodion  plate.  In  the  mean  while  the 
model  remains  quite  still.  The  shutter  is  again  opened  and 
the  plate  exposed  as  before. 

Development. 

This  operation  scarcely  needs  any  elucidation ;  the  proper 
negative  effect  has  to  be  attained  by  means  of  the  reducing 
agent  and  the  intensifier  as  before  minutely  described.  The 
image  is  by  far  softer,  and  in  other  respects  more  agreeable, 
if  the  negative  can  receive  its  requisite  amount  of  density  by 
the  primary  development,  or  nearly  so,  so  that,  when  inten- 
sified, but  little  more  has  to  be  accomplished,  and  this  little 
can  be  effected  by  a  weak  intensifier.  When  the  strengthen- 
ing solution  is  very  strong,  it  is  apt  to  engender  a  pulveru- 
lent deposit  on  the  surface  of  the  collodion  which  detracts 
from  softness  and  sharpness,  communicating  to  the  photo- 
graph an  appearance  of  measles  or  small-pox.  In  this  re- 
spect it  is  indifferent  whatever  may  be  the  size  of  the  nega- 
tive, where  there  is  a  tendency  to  this  powdery  phenomenon, 
whether  it  arise  from  the  collodion,  or,  as  I  have  just  re- 


220 


THE  CAED-PICTURE. 


marked,  from  a  deposit  of  the  silver,  it  is  always  advisable 
to  intensify  slowly. 

One  point  in  the  taking  of  negatives  I  have  not  yet  ad- 
verted to.  In  the  wet  process,  if  the  sensitized  plate  has  to 
wait  long  between  the  time  of  its  removal  from  the  silver 
bath  and  its  development,  the  silver  solution  evaporates  ra- 
pidly, and  the  plate  becomes  dry,  or  nearly  so ;  the  conse- 
quence of  this  is  supposed  to  be,  that,  as  the  solution  thus  be- 
comes stronger,  it  dissolves  the  iodide  of  silver  in  the  film, 
and  gives  rise  to  the  phenomenon  of  minute  apertures.  With- 
out attaching  much  credit  to  this  rationale  of  a  trouble  which 
is  very  annoying,  we  do  know  that  if  the  silvered  plate  be- 
comes dry  the  development  is  very  irregular.  Another  cause 
of  the  minute  apertures  alluded  to  is  a  quantity  of  insoluble 
bromide  in  the  collodion.  It  is  a  recommendation,  therefore, 
to  dissolve  the  iodides  and  bromides  in  the  preparation  of 
collodion,  first  in  alcohol,  and  to  filter  the  solution,  after 
standing  several  hours,  before  it  is  added  to  the  plain  collo- 
dion. Another  reason,  and  probably  a  very  frequent  one,  is 
to  be  traced  to  the  minute  insoluble  particles  in  the  silver 
bath,  which  settle  upon  the  tender  collodion  film,  and  become 
as  it  were  imbedded  in  it.  These  in  the  subsequent  opera- 
tions of  developing  and  fixing  produce  either  opaque  pulver- 
ulent black  points,  or  transparent  ones,  just  as  they  retain  a 
fixed  position  in  or  on  the  film,  or  are  washed  or  dissolved  off. 
Both  these  phenomena  are  exceedingly  annoying.  Such  a 
cause  can  be  removed  by  filtration,  or  by  a  sort  of  coagula- 
tion, (if  I  may  use  the  word  here  instead  of  precipitation,) 
by  means  of  a  small  quantity  of  a  solution  of  salt,  and  then 
by  filtration.  This  operation  certainly  weakens  the  bath, 
but  it  makes  it  at  the  same  time  a  better  solvent  of  certain  im- 
purities that  tend  to  cause  the  trouble  in  question.  The  ten- 
dency to  these  horrid£>m-Aofes  is  greater  when  the  bath  is  strong 
than  when  it  is  weak  ;  it  would  appear,  however,  that  the  in- 
soluble iodide  of  silver  in  the  film  can  scarcely  be  a  cause  of 
the  trouble;  for  being  present  everywhere  in  the  film,  it 
would  be  uniformly  dissolved  as  the  silver  solution  gradually 
increased  in  strength,  and  would  thus  present  a  condition  for 
actinism  the  very  best  that  could  be  desired.  There  is  cer- 
tainly no  doubt  that  these  apertures  are  caused  in  the  ma- 
jority of  cases  by  an  insoluble  pulverulent  substance,  loosely 
attached  to  the  surface  of  the  collodion,  and  either  sensitive 
to  the  actinic  rays  or  not,  (which  is  quite  immaterial  to  the 
argument ;)  these,  imbedded  on  the  surface  of  the  collodion 
and  opaque,  prevent  the  rays  from  penetrating  to  the  true 


THE  CARD-PICTURE. 


221 


film  beneath,  and  being  afterward  brushed  off  or  dissolved 
off  by  the  acids  in  the  developer  or  by  the  fixing  solution, 
expose  parts  in  which  the  iodides  and  bromides  have  not  un- 
dergone the  luminous  influence,  and  are  hence  made  trans- 
parent by  the  hyposulphite  of  soda,  like  any  other  protected 
part. 

In  fine,  no  general  rule  is  known  by  which  a  priori  these 
pin-holes  can  always  he  avoided  and  accounted  for. 

The  card-negative,  next  to  that  which  is  prepared  for  the 
solar  camera,  must  be  bright  and  transparent,  free  from  the 
slightest  trace  of  mistiness  or  fogging,  and  of  such  a  depth 
of  shade  as  to  preserve  the  whites,  whilst  at  the  same  time 
the  operation  of  printing  is  performed  quickly.  That  the 
negative  must  be  sharp  is  a  sine  qua  non  y  and  in  order  that 
the  negative  be  sharp  and  well-defined  to  the  very  edge, 
and  from  top  to  toe,  spare  no  expense,  no  trouble  in  securing 
a  reliable  lens.  With  this,  and  a  moderate  share  of  intelli- 
gence, an  operator  may  run  his  career  without  impediment 
to  success ;  whilst  his  neghbors,  with  poor  lenses,  whatever 
their  amount  of  education,  will  roll  down  the  hill  to  perdition. 
The  lens  leads  to  success  or  to  ruin. 

Fixing. 

There  is  no  difference  in  this  department  from  that  which 
will  be  found  in  reference  to  the  melainotype,  or  the  ordi- 
nary negative.  Either  cyanide  of  potassium  or  hyposulphite 
of  soda  is  used.  The  new  fixing  agent,  sulphocyanide  of 
ammonium,  it  appears  has  no  claims  of  superiority  over  its 
predecessors ;  it  has,  however,  a  decided  disadvantage,  and 
that  is  its  expense;  this  will  always  exist  comparatively, 
because  cyanide  of  potassium  can  more  easily  be  manufac- 
tured. Like  the  cyanide,  too,  it  has  toxical  properties.  In 
order  to  avoid  all  the  poisonous  effects  that  might  arise  from 
contact  of  such  substances  with  the  broken  skin  or  wounds, 
as  well  as  the  discoloration  of  the  skin  from  the  silver  salts 
during  development,  I  would  recommend  a  plan  which  I 
generally  adopt.  I  do  not  hold  the  negative  in  the  hand 
when  I  intensify ;  it  is  placed  on  a  piece  of  glass  cut  out 
in  the  form  of  the  porcelain  dipper  for  the  silver  b^ath.  At 
one  end  a  small  piece  of  thick  glass,  one  inch  in  width,  and 
as  long  as  the  dipper  is  wide,  is  cemented  by  melted  lac ; 
over  this  is  cemented  a  second  piece,  projecting  above  the 
first  one,  so  as  to  form  a  ledge  beneath  which  the  nega- 
tive is  kept  in  its  place.  At  the  upper  end  the  negative  is 
secured  in  its  place  by  means  of  a  clothes-pin.  In  this  way  the 


222 


THE  CARD-PICTURE. 


negative  can  be  intensified  without  obscuring  the  light  that 
passes  through  it  from  below,  and  the  hand  at  the  same  time 
is  protected  from  contact  with  the  pyrogallic  acid  and  silver. 
Stains  from  nitrate  of  silver,  or  from  the  pyrogallate  can  be 
removed,  it  is  true,  as  long  as  they  have  not  been  exposed 
much  to  light,  by  washing  with  cyanide  of  potassium ;  but 
this  would  entail  upon  the  operator  the  trouble  of  washing 
after  each  negative,  and  might  entail  upon  him  incurable  ul- 
cers. If  he  does  not  wash  his  hands  after  each  negative  has 
been  taken,  there  is  no  alternative,  they  must  inevitably  be- 
come black.  The  glass  dipper  will  obviate  this  trouble.  An- 
other trouble,  but  not  quite  so  alarming,  arises  from  the  mode 
we  practise  of  turning  the  prints  round  with  the  hands  in  the 
toning  and  fixing  baths.  The  health  of  operators  is  much 
impaired,  and  especially  in  those  large  printing  establish- 
ments, where  a  number  of  females  are  employed  in  this  de- 
partment, who,  by  this  continual  manipulation  in  the  two 
fluids,  are  frequently  in  a  suffering  condition  Now  all  this 
can  be  avoided  by  a  dexterous  use  of  a  glass  rod,  well  rounded 
off  at  either  end,  and  held  in  either  hand.  The  hands  have 
no  business  in  these  fluids  /  and  all  parties  concerned,  that  is, 
hands ^fluids ,  and  prints,  will  be  benefited  by  following  the 
precaution  recommended.  With  a  little  ingenuity  a  pair  of 
porcelain  or  glass  forceps  might  be  constructed  for  this  spe- 
cial purpose,  consisting  of  porcelain  or  glass  legs  fastened 
into  a  steel  spring  arch,  which  would  hold  them  an  inch  or 
so  asunder.  Such  forceps  may  be  used,  too,  in  holding  the 
negative  either  during  development  or  intensifying.  The 
health  of  the  photographer  has  to  be  looked  to,  and  means 
adopted  for  its  preservation. 

Printing  of  Card -Pictures. 
There  is  nothing  peculiar  in  the  printing  of  card-pictures, 
photographically  speaking,  as  distinct  from  that  in  other  pic- 
tures on  paper,  except  it  be  the  number  of  photographs  on 
the  same  plate  ;  for,  as  was  to  be  inferred  from  the  manner 
prescribed  to  take  the  negative,  this  plate  may  contain  as 
many  as  sixteen  distinct  pictures ;  it  seldom,  however,  con- 
tains as  many.  Condensing  reflectors  find  their  application 
here  to  great  advantage  when  the  light  is  dull  Such  an  ar- 
rangement of  reflectors  might  be  constructed  on  a  movable 
platform,  or  turn-table,  capable  of  rotating  horizontally, 
whilst  the  frustum  itself,  lined  by  the  reflectors,  and  sup- 
ported on  vertical  pillars,  has  a  vertical  motion.  By  the 
two  motions  combined,  the  frustrum  can  be  easily  brought 


THE  CARD-PICTURE. 


223 


in  front  of  the  direct  rays  of  the  sun,  whereby  a  great  con- 
densation of  light  can  be  effected  on  any  given  surface.  It 
is  immaterial  how  large  a  surface  may  be  occupied  by  the 
negative,  or  the  sum  of  the  negatives  on  the  same  plate, 
reflectors  can  be  made  in  accordance,  possessing  the  advan- 
tage of  the  direct  rays  that  strike  the  plate,  as  in  ordinary 
printing,  together  with  the  extra  advantage  of  the  condensed 
light  from  the  rays  after  one  reflection,  as  well  as  from  those 
after  two  reflections.  The  size  of  each  of  the  reflectors  al- 
luded to  will  be  proportionate  to  that  given  in  a  preceding 
chapter.  If  the  negative  plate  be  sixteen  inches  square,  then  it 
will  be  four  times  as  large  in  its  linear  dimensions,  as  in  the  ex- 
ample given  ;  consequently,  multiplying  14//T  an^  ^IfW  DV 
this  ratio,  that  is  4,  we  obtain  59^^  and  85  inches  for  the 
length  of  the  upper  or  larger  base,  and  86T\4o  inches  for  the 
length  of  the  side  of  each  plate  of  glass  in  the  frustum.  Such 
a  machine,  of  course,  will  be  expensive,  but  like  a  wind-mill 
where  no  water  exists,  it  will  soon  pay  for  its  construction 
by  economizing  time.  By  such  a  condensation  of  the  sun's 
rays,  a  negative  will  print  well  in  from  thirty  to  sixty  seconds, 

Vignette  Printing, 

A  vignette  is  a  picture  of  a  portrait,  consisting  of  the  head 
and  part  of  the  bust,  of  an  oval  shape,  in  the  middle  of  the 
card,  surrounded  by  a  sort  of  halo,  or  shading  off  gradually 
into  the  white  background. 

For  this  sort  of  printing  the  operator  has  to  be  furnished 
with  vignette  glasses,  which  are  manufactured  specially  for 
such  operations,  and  to  be  had  of  all  respectable  dealers. 
The  vignette  aperture  can  be  had  of  any  size  required ;  it  is 
formed  of  a  piece  of  glass,  stained  on  one  or  on  either  side 
with  a  metallic  oxide,  which  is  burnt  into  the  glass.  This 
stain,  however,  is  a  mere  film,  and  can  easily  be  ground  away 
of  the  requisite  shape  and  size  by  the  lapidary,  and  then  pol- 
ished. The  external  parts  being  of  a  red  orange  color,  in- 
tercept or  absorb  those  rays  of  light  which  would  act  upon 
the  sensitized  collodion  film,  whilst  through  the  vignette 
opening  all  the  rays  can  act  almost  with  their  primitive 
vigor.  Such  a  glass,  or  an  appendage  of  such  glasses,"  is 
placed  first  on  the  glass  of  the  printing-frame ;  upon  this 
comes  the  negative,  and  then  the  paper,  as  in  ordinary  print- 
ing arrangements. 

Vignette  glasses  can  be  made  by  the  photographer  himself 
in  the  following  manner  :  Take  a  piece  of  glass  of  the  proper 
6ize,  and  paint  either  with  water  or  oil  colors  the  vignette 


224 


THE  CARD-PICTURE. 


opening  in  orange  or  black,  shading  off  toward  the  edges ; 
fill  up  the  remaining  part  with  white  paint,  shading  the  edges 
bordering  on  the  vignette  gradually  deeper  and  deeper,  unti) 
the  layer  becomes  uniformly  white  to  the  edges  of  the  glass. 
This  is  the  matrix  from  which  an  indefinite  number  of  nega- 
tives can  be  copied,  which  will  be,  when  varnished,  the  vig- 
nettes required. 

Toning,  Fixing,  and  Mounting. 
No  further  observations  are  requisite.  Instructions  on 
these  matters  are  given  in  detail  in  a  preceding  chapter  of 
this  work,  and  on  the  coloring  of  the  card-picture,  of  the  ste- 
reograph and  the  photograph  in  a  chapter  specially  devoted 
to  the  subject. 

On  the  Tinting  and  Coloring  of  Photographs. 

The  colors  required  to  tint  or  color  photographs  are  the 
same  as  those  employed  in  miniature  painting,  and  the  same 
amount  of  artistic  skill  is  required  in  the  one  as  in  the  other, 
where  excellence  and  perfection  are  the  aim  of  the  photo- 
grapher. Where  very  large  photographs  are  to  be  colored, 
the  fineness  of  miniature  painting  for  hatching  or  stippling 
is  not  essential,  in  fact  it  would  be  out  of  place ;  in  such  a 
case  a  knowledge  of  crayon-drawing  is  brought  to  bear  on 
the  subject.  Colors  for  such  artistic  purposes  exist  in  three 
forms  :  in  cakes,  in  powders,  in  liquids,  in  oil,  and  in  crayons. 

For  touching  up  daguerreotypes,  ambrotypes,  melainotypes, 
and  ferrotypes,  colors  in  very  fine  powder  are  employed. 
These  are  laid  on  the  appropriate  parts,  shaded  off  so  that 
no  sharp  edges  exist,  and  afterward  the  excess  is  blown  off 
with  an  India-rubber  blower,  either  before  the  application  of 
the  varnish  or  afterward,  or  both  before  and  afterward,  as 
in  the  alabastrine  process,  where  the  color  is  laid  on  some- 
times three  or  four  times,  until  it  shows  through  to  the  other 
side. 

Liquid  colors,  that  is,  the  new  Aniline  colors,  are  spe- 
cially adapted  for  the  tinting  and  coloring  of  albumen  pic- 
tures ;  these  colors  flow  very  easily,  and  the  albumen  surface 
requires  no  preparation.  For  the  ordinary  photographic 
practitioner  in  card-pictures  they  are  to  be  highly  recom- 
mended. 

Where  the  card-picture  or  photograph  is  to  be  colored, 
hatched  and  stippled  to  perfection  in  the  form  of  a  miniature 
painting,  the  artist  requires  a  complete  outfit  of  Newman's 
photographic  colors,  etc.    It  is  remarkable,  however,  to  see 


THE  CARD-PICTURE. 


225 


with  how  few  colors  the  real  artist  can  execute  the  most  fin- 
ished work. 

The  Colors  used  most  frequently. 
Chinese  white,  Naples  yellow,  raw  sienna,  burnt  sienna, 
yellow  ochre,  yellow  lake,  ivory  black,  bistre,  gamboge,  cobalt 
blue,  Prussian  blue,  indigo,  Chinese  vermilion,  scarlet  lake, 
neutral  tint,  sap  green,  carmine,  rose  madder,  purple  lake, 
Venetian  red,  pink  madder,  and  sepia.  These  are  in  the 
form  of  cakes.  To  these  may  be  added  a  few  bottles  of 
liquid  colors,  as  of  silver  white,  chrome  yellows,  greens,  etc. 

Other  Indispensable  Articles. 
Sable,  fitch,  and  camel's  hair  pencils,  prepared  ox-gall, 
brushes,  shells,  stumps,  slabs,  palettes,  varnish,  gum-arabic, 
gelatine,  penetrating  varnish,  eraser,  basin,  tumbler,  and 
sponge. 

Coloring  of  a  Portrait. 
In  regard  to  coloring  as  to  photography,  I  shall  treat  the 
subject  of  shading  as  divisible  into  three  parts  :  lights,  mid- 
dle tones,  and  shades.  An  irregular  surface  has  always 
these  three  gradations,  not  separated  by  distinct  lines  of 
demarkation,  but  flowing  gradually  or  irregularly  into  one 
another,  according  as  the  undulations  of  the  surface  are  gra- 
dual or  irregular.  Difference  of  distance  in  a  plain  surface 
effects  what  irregularity  effects  on  an  undulating  surface, 
whose  parts  are  nearly  all  at  the  same  distance.  Supposing 
then  a  surface  of  one  and  the  same  uniform  color  gradually 
retires  from  the  eye,  it  is  evident  that  the  nearest  parts  are 
the  most  brilliant  and  light,  the  middle  parts  less  so,  and  the 
most  distant  parts  are  the  darkest  and  least  brilliant.  So  it 
is  also  with  undulating  surfaces,  the  most  prominent  parts 
are  the  lights  or  the  bright  parts ;  the  depressions  or  cavi- 
ties, the  shades  or  darkest  parts:  and  the  retiring  or  interme- 
diate parts  are  the  middle  tones.  This  is  the  effect  of  light 
and  distance,  and  we  have  to  imitate  this  only  in  color  on  a 
plane  surface,  for  the  gradations  of  shade  are  already  im- 
pressed in  tile  photograph.  The  question  to  be  solved  then  is 
simply  this  :  there  are  three  differen  t  degrees  of  the  same  color 
in  a  given  space — which  is  the  most  appropriate  manner  of  ob- 
taining this  collocation  or  rather  gradation  of  these  shades 
of  color  ?  Without  the  slightest  pretension  to  dictate  artist- 
ically on  a  subject  that  takes  much  genius  and  incessant  la- 
bor to  attain  to  perfection,  I  recommend  to  the  photographer, 
who  aims  to  ameliorate  his  photographs  somewhat  respecta- 
bly with  color,  to  lay  on  the  middle  tint  first  over  the  whole 


226 


THE  CARD-PICTURE. 


surface,  and  then  the  lights  and  shades  afterward,  in  their 
proper  places,  when  the  first  is  dry.  To  be  enabled  to  do 
this,  select  three  gradations  of  the  color  in  question.  It  some- 
times happens  that  the  white  of  the  paper  forms  the  lights ; 
in  this  case  the  dark  parts  may  be  laid  on  and  shaded  off  into 
the  lights. 

Coloring  the  Face. 

Paste  the  photograph  on  a  piece  of  cardboard  in  the  first 
place,  varnish  the  surface  with  Newman's  preparation,  and 
then  proceed  as  follows  :  Lay  on  cobalt  blue  in  small  quantity 
in  all  the  shades  and  depressions  of  the  face  with  a  light  hand 
and  small  pencil,  as,  for  instance,  along  where  the  roots  of  the 
hair  commence,  about  the  temples,  about  the  chin,  beneath 
the  eyebrows,  and  around  the  eyelashes,  etc.  With  another 
pencil  dipped  in  water,  so  as  simply  to  moisten  it,  spread  the 
color  so  as  to  dilute  it  and  shade  it  off,  so  that  it  becomes 
more  and  more  transparent,  until  it  finally  reaches  the  bright 
lights  and  merges  into  them.  You  proceed  in  like  manner 
with  the  interior  of  the  eyes,  that  is,  on  the  visible  parts  of 
the  sclerotic  or  white  of  the  eye.  The  object  of  this  opera- 
tion with  cobalt  blue  is  to  give  more  softness  to  the  dark 
shades  afterward.  The  veins  of  the  hand,  the  borders  of  the 
coat,  waiscoat,  etc.,  and  the  cuffs  of  the  sleeves  where  they 
terminate  on  the  linen,  have  to  be  treated  in  like  manner, 
beginning  with  the  darkest  part  and  shading  off  into  the 
lightest.  Allow  this  color  to  dry,  and  in  the  mean  while  j3i*e- 
pare  the  colors  for  the  face,  neck,  hands,  etc. 

For  a  person  of  fresh  complexion  mix  up  a  little  yellow 
ochre,  with  one  third  the  quantity  of  vermilion  and  pink 
lake  in  water  on  the  palette  or  slab,  and  cover  the  face, 
(with  the  exception  of  the  eyes,)  the  arms,  the  hands,  etc., 
with  a  thin  and  uniform  layer  of  this  mixture ;  then  tint  im- 
mediately the  cheek-bones  and  other  prominences  with  a  very 
thin  mixture  of  rose  madder  and  vermilion,  in  order  to  give 
more  animation  to  these  parts  above  the  rest.  If  the  person 
has  a  red  complexion,  these  colors  are  heightened  still  more ; 
and  where  the  complexion  is  very  pale,  less  vermilion  is  used, 
and  no  color  on  the  cheeks.  The  upper  lip,  being  in  shade, 
must  be  tinted  wTith  a  mixture  of  cobalt  blue  and  lake,  whilst 
vermilion  is  employed  for  the  lower. 

For  a  sun-burnt  complexion,  add  to  the  colors  indicated  a 
small  quantity  of  bistre,  and  proceed  with  the  general  wash 
as  before ;  follow  up  with  lake  and  vermilion  for  cheeks, 
where  they  are  colored,  and  use  nothing  where  they  arc  pale. 
Where  yellow  prevails  in  the  complexion,  increase  the  ochre. 


THE  CARD-PICTURE. 


227 


Where  a  simply  tinted  picture  is  required,  the  operation  may 
stop  here ;  but  where  a  higher  finish  is  desired;,  you  may  pro- 
ceed and  stipple  in  a  light  tint  of  lake  and  vermilion  on  the 
bright  parts  of  the  cheeks,  lips,  etc.,  by  using  a  very  fine- 
pointed  pencil,  and  filling  up  the  parts  with  contiguous  fine 
dots  or  points  of  color  ;  and  by  hatching  over  the  shadows  on 
the  forehead  and  the  retiring  parts,  the  temples  and  the  chin 
with  a  bluish-gray  color,  that  is,  fill  up  these  parts  with  con- 
tiguous short  lines,  and  then  cross  them  in  a  similar  manner, 
so  as  to  produce  a  greater  depth  of  shade.  Use  a  little  pink 
madder  in  the  corner  of  the  eye  next  the  nose ;  stipple  the 
lips  too,  and  mix  a  little  Chinese  white  with  the  lake  and 
vermilion  for  the  high  lights.  The  edge  of  the  eyelids  have 
to  be  treated  in  a  similar  way.  Stippling  and  hatching  are 
more  especially  required  where  the  colors  have  not  been 
neatly  laid  on  in  the  first  operations.  We  now  proceed  to 
the  hair. 

Blonde  Hair. 

Wash  the  entire  surface  of  the  hair  with  a  mixture  of  yel- 
low ochre  and  bistre  in  small  quantity  ;  then  soften  the  colors 
down  where  they  border  on  the  temples  and  the  forehead 
with  a  pencil  dipped  in  water.  As  soon  as  this  wash  is  dry, 
take  a  very  fine  long  pencil  and  proceed  to  introduce  the 
dark  parts  with  a  mixture  of  ochre  containing  more  bistre. 
The  lights  are  produced  by  adding  either  a  little  white  or 
Naples  yellow  to  the  original  mixture  of  yellow  ochre  and 
bistre.  Both  the  lights  and  shades  are  introduced  by  streaks 
of  color  in  the  direction  of  the  hair,  taking  care  to  avoid  the 
wiry  effect  produced  by  making  each  hair  separately.  Soften 
down  those  parts  that  border  on  the  background,  and  stipple 
up  those  parts  along  the  roots  of  the  hair  with  cobalt  blue  or 
gray,  lest  the  boundary  of  the  hair  should  be  too  marked, 
and  give  it  the  appearance  of  being  inlaid. 

Chestnut  -  Colored  Hair. 
Cover  the  whole  with  a  layer  of  bistre  ;  then  finish  up  the 
shades  with  a  mixture  of  ivory  black  and  bistre,  the  lights 
with  Naples  yellow  and  bistre,  and  the  high  lights  with  a 
little  white  mixed  with  cobalt. 

Black  Hair. 

The  general  wash  for  such  hair  is  ivory  black  diluted  with 
water ;  the  dark  shades  are  put  in  with  ivory  black  of  greater 
consistency,  and  the  lights  with  the  same  color,  mixed  with 
white  and  cobalt  if  the  hair  is  blue-black,  and  with  white  and 
a  little  pink  madder  if  the  hair  is  of  a  pure  black.  - 


228 


THE  CARD-PICTURE. 


Gray  Hair. 

Cover  tlie  whole  with  a  mixture  of  equal  quantities  of  bis- 
tre and  white  ;  the  dark  parts  w^ith  bistre  and  a  less  quantity 
of  white ;  the  lights  with  bistre  and  more  white  than  in  the 
general  wash,  and  the  high  lights  with  cobalt,  white,  and 
pink  madder. 

Red  Hair. 

Take  yellow  ochre  and  burnt  sienna  for  the  general  tint ; 
the  same  and  a  little  bistre  for  the  shades ;  white,  yellow 
ochre  and  burnt  sienna  for  the  intermediate  lights ;  white, 
cobalt  and  lake  for  the  high  lights. 

White  Hair. 

The  general  tint  is  that  of  the  photograph  itself ;  the  shades 
are  put  in  with  a  little  black,  and  a  very  small  portion  of 
yellow  ochre  and  cobalt,  and  the  lights  with  Chinese  white. 

The  head  and  face  may  now  be  considered  nearly  finished ; 
all  that  remains  to  be  done  is  to  put  in  the  deep  touches  about 
the  eyes  with  sepia  and  pink  madder,  worked  up  with  a  little 
gum-arabic  ;  those  about  the  nose  are  put  in  with  sepia  and 
gum-water.  Put  in  the  light  in  the  pupil  of  the  eye  with 
Chinese  white.  All  these  final  touches  require  great  care 
and  skill. 

The  hand,  the  neck,  the  shoulders,  etc.,  are  retouched  with 
the  final  stipplings  or  hatchings  in  the  same  way,  in  order  to 
give  animation  to  the  picture,  observing  to  put  in  greys  or 
cobalt  blue  in  the  shades,  and  pink  madder  in  the  bright 
lights. 

Drapery. 

The  handsomest  drapery  is  black.  The  general  wash  is 
ivory  black  of  the  consistency  of  ink.  This  is  laid  on  uni- 
formly with  a  full  pencil,  beginning  at  the  top  and  proceed- 
ing downward  to  the  lowest  edge,  the  picture  being  inclined 
during  this  operation.  All  excess  is  removed  with  a  dry 
pencil,  and  the  layer  is  allowed  to  dry.  When  dry,  the  dark 
shades  are  put  in  with  ivory  black,  of  greater  consistency, 
and  the  lights  with  ivory  black,  mixed  with  Chinese  white 
and  pink  madder. 

In  all  cases  of  tinting  or  coloring  with  any  degree  of  re- 
finement, it  is  indispensable  for  the  beginner  to  be  provided 
with  two  photographs  of  the  model,  one  to  receive  the  color, 
and  the  other  to  serve  as  guide  for  the  introduction  of  the 
shades,  in  case  they  become  obliterated  in  the  general  wash. 


THE  CARD-PICTURE. 


229 


Blue  Drapery. 
The  general  tint  consists  of  Prussian  blue,  or  indigo,  as 
the  case  may  require,  mixed  with  a  little  black  and  pink 
madder ;  the  dark  parts  are  put  in  with  the  same  mixture, 
containing  more  black,  and  the  lights  with  the  same,  con- 
taining an  admixture  of  white.  For  light  blues,  cobalt  blue 
may  be  used  ;  and  the  lights  may  be  obtained  by  proceeding 
with  a  pencil  dipped  in  water  over  the  parts,  so  as  to  remove 
a  portion  of  the  color. 

Green  Drapery. 
Cover  the  dress  with  a  mixture  of  yellow  lake  and  Prus- 
sian blue  ;  and  throw  in  the  shades  with  the  same  color,  mixed 
with  a  little  black  and  pink  madder.  The  lights  are  put  in 
with  emerald  green,  and  the  high  lights  with  this  color,  mixed 
with  a  little  white. 

Red  Drapery. 

The  general  wash  consists  of  vermilion,  mixed  with  a  little 
pink  madder  diluted  with  water.  Add  to  this  a  little  bistre 
or  black  for  the  dark  shades,  and  Naples  yellow  or  white  in 
place  of  bistre  for  the  lights. 

Rose  -  Colored  Drapery. 
Rub  up  pink  madder  with  the  requisite  quantity  of  water 
for  the  general  wash  ;  to  this  add  a  little  black  for  the  shades, 
and  a  little  white  for  the  lights. 

Drown  Drapery. 
Use  burnt  sienna,  with  a  small  portion  of  black  bistre  for 
the  general  tint ;  for  the  shades  add  a  little  black,  and  for 
the  lights  a  little  white. 

Pink  Drapery. 
Cover  the  dress  with  a  dilute  solution  of  pink  madder ; 
then  put  in  the  shades  with  a  mixture  of  pink  madder,  black 
and  cobalt ;  and  the  lights  with  pink  madder  and  Chinese 
white. 

White  Drapery. 
The  general  tint  is  cobalt,  much  diluted ;  yellow  ochre, 
cobalt  and  a  little  black  form  the  shades,  and  Chinese  white 
is  used  for  the  lights. 

Yelloio  Drapery. 
Any  of  the  yellows,  as  yellow  ochre,  yellow  lake,  gamboge, 
or  chrome  yellow,  diluted  with  water,  may  be  used  for  the 
ground  color ;  a  little  bistre  added  to  the  yellow  forms  the 


230 


THE  CARD-PICTURE. 


dark  p.xrts ;  and  a  little  white  to  the  yellow  is  used  to  pro 
duce  the  lights. 

Pearl  Gray.  . 
Mix  a  little  cobalt,  black  and  pink  madder  for  the  ground 
color ;  add  to  this  Chinese  white  for  the  lights ;  for  the 
shades  use  a  mixture  of  ivory  black  and  cobalt. 

Violet. 

Take  equal  quantities  of  Prussian  blue  and  pink  madder 
for  the  general  wash ;  white  and  this  mixture  produce  the 
lights  ;  and  neutral  tint  is  used  for  the  shades. 

Background. 

The  background  must  ux$  secondary  in  effect  to  the  real 
object  in  the  picture ;  as  a  general  rule,  it  must  be  lighter 
than  the  shades  of  this  object,  and  darker  than  the  lights. 
Avoid  the  appearance  of  inlaying  the  object  or  portrait  in 
the  background.  This  can  be  done  by  the  appropriate  use 
of  shadow,  which  can  be  made  to  throw  the  background  far 
into  the  distance  behind. 

A  similar  uniform  flat  tint  is  laid  on  as  already  described 
for  the  drapery.  Where  defects  exist  in  the  photograph,  a 
general  wash  is  first  laid  on  and  then  pulverized  crayon  of 
the  proper  color  is  rubbed  on  this,  when  dry,  by  means  of 
the  finger,  and  in  those  parts  in  contiguity  with  the  figure 
with  a  fine  stump.  Curtains,  pillars,  tables,  etc.,  are  put  in 
precisely  in  the  same  way  as  drapery  ;  only  be  very  cautious 
not  to  make  these  the  principal  objects  of  the  picture  by 
extreme  definition  and  brilliancy  of  color.  They  must  be 
thrown  into  the  background  by  less  intensity  of  color,  and 
by  a  general  feebleness  of  outline. 

How  to  Imitate  Metals,  etc.,  with  Color. 

The  artist  does  not  use  the  metals  themselves  in  miniature 
painting ;  it  would  be  an  insult  to  art  to  request  their  use. 
They  can  all  be  imitated  by  color  as  follows  : 

Gold. — Take  an  equal  quantity  of  yellow  lake  and  yellow 
ochre,  and  a  very  small  quantity  of  burnt  sienna,  and  mix 
them  together  on  the  slab,  and  cover  the  part  desired  with 
this  mixture.  As  soon  as  this  foundation  color  is  dry,  use 
burnt  sienna  alone  for  the  shades.  The  lights  are  formed 
of  chrome  yellow,  and  are  completed  in  the  high  lights  with 
a  little  Chinese  yellow. 

Silver. — Mix  yellow  ochre  and  cobalt  in  equal  quantities 
together  with  a  small  portion  of  ivory  black  ;  this  forms  the 


THE  CARD-PICTURE. 


231 


ground-work.  The  shades  are  made  with  a  little  neutral 
tint  or  ivory  black ;  and  the  lights  with  Chinese  white  laid 
on  with  a  firm  touch. 

Iron, — The  ground-work  consists  of  cobalt  blue,  with 
small  portions  of  black  and  yellow  ochre.  The  shades  are 
made  with  neutral  tint  and  a  small  quantity  of  ochre ;  the 
lights  consisting  of  white,  tinted  slightly  with  black. 

Mother  of  Pearl. — This  substance  takes  light  in  the  pho- 
tograph ;  there  is  no  ground-tone  ;  put  in  a  very  light  tint 
of  cobalt  blue,  as  also  of  very  light  pink  madder  in  two  or 
three  places,  taking  care  they  do  not  come  in  contact ;  the 
shades  are  then  formed  of  black  ochre  and  cobalt ;  and  the 
lights  with  Chinese  white. 

Lace,  etc. — Lay  on  a  general  tint  of  ivory  black  somewhat 
deeper  than  that  of  the  dress ;  the  meshes  are  then  intro- 
duced with  white  mixed  with  a  little  blue  and  black.  The 
design  is  finished  by  indicating  it  with  Chinese  white. 

Precious  Stones. — Rubies,  sapphires,  emeralds,  etc.,  receive 
a  foundation  of  neutral  tint  of  considerable  consistency; 
Chinese  white  is  put  on  the  luminous  part ;  whereas  the  re- 
flection, which  is  on  the  opposite  side  to  the  luminous  part, 
receives  the  color  of  the  stone.  The  diamond  alone,  owing 
to  its  nature,  has  a  reflection  of  a  more  dead  white. 

As  soon  as  the  portrait  is  finished,  pass  over  the  eyes,  the 
hair,  the  eye-lashes,  the  nose,  and  the  mouth,  lightly  with  a 
solution  of  gum ;  do  the  same  also  with  satin  stuffs,  such  as 
collars,  waistcoats,  and  robes.  Used  in  moderation,  this  so- 
lution communicates  a  vigor  and  freshness  to  the  picture 
which  are  quite  satisfactory. 

(The  preceding  article  on  tinting  and  coloring  is  extracted 
almost  entirely  from  the  small  work  on  this  subject  by  Hilaire 
David.) 


CHAPTBE  XXXVI. 


DRY  COLLODION  PROCESS  DRY  PROCESSES. 

My  instructions  hitherto  have  been  limited  strictly  to  the 
chemical  and  mechanical  manipulations  that  occur  in  that 
department  of  photography  denominated  the  Wet  Collodion 
Process.  This  process  will  ever  remain  the  predominant 
mode  of  conducting  photographic  operations  in  the  room  ; 
it  is  preferred,  too,  by  many  tourists  in  the  field.  The  in- 
convenience, however,  of  dragging  along  over  mountain  and 
valley,  or  of  stowing  away  on  steamer  or  on  the  cars,  a  com- 
plete miniature  operating  gallery,  has  suggested  the  idea  of 
superseding  all  this  trouble  by  the  discovery  of  a  dry  process. 
Several  processes  have  been  discovered  which  are  more  or 
less  successful,  and  all  very  practical ;  but  it  must  be  con- 
fessed that  the  same  degree  of  sensitiveness  in  the  dry  pro- 
cess has  not  yet  been  attained  as  in  the  wet  process — instan- 
taneous pictures  are  the  result  only  of  the  latter.  It  appears 
natural  for  us  to  expect  such  a  result;  chemical  combina- 
tions and  reductions  are  effected  most  easily  when  the  mole- 
cules of  matter  are  in  such  a  condition  as  to  have  freedom 
of  locomotion,  by  which  new  molecular  arrangements  can  be 
formed,  in  accordance  with  the  new  electro-chemical  attrac- 
tions and  repulsions  superinduced  by  the  contact  of  dissimi- 
lar bodies. 

For  landscape  and  especially  for  architectural  photogra- 
phy, for  copying,  as  well  as  for  every  case  of  photography  in 
still  life,  where  the  time  of  exposure  is  not  important,  dry 
plates  are  decidedly  superior  to  wet  ones  because  of  the  uni- 
formity of  their  condition  during  the  time  of  their  exposure : 
wet  plates,  on  the  contrary,  by  desiccation  are  continually 
changing ;  and  one  of  these  changes  —  the  concentration  of 
the  nitrate  of  silver  during  evaporation  —  is  supposed  to  be 
one  of  the  causes  that  produce  minute  apertures  in  the  film, 
and  is  certainly  the  cause  of  an  irregularity  in  the  reduction- 
process  during  development.    The  aim  of  a  dry  plate  is  to 


DRY  COLLODION  PROCESS. 


233 


attain  to  a  maximum  of  preservation  of  the  sensitiveness  for 
an  indefinite  time.  It  lias  happened  hitherto  that  the  ratio 
of  this  preservation  is  inversely  as  the  time  of  exposure,  or, 
probably  in  plainer  terms,  that  the  better  the  plate  is  pre- 
served so  as  to  retain  sensitiveness,  the  longer  the  time  re- 
quired to  be  exposed  to  the  actinic  influence  to  produce  a 
given  effect.  The  theory,  that  is,  the  rational  elucidation 
of  the  action  of  reduction  in  a  dry  plate  is  still  a  problem  ; 
if  the  wet  plate,  after  sensitization,  be  thoroughly  washed 
and  then  exposed,  no  picture  is  developed  by  the  reducing 
agent ;  but  in  the  dry  plate  the  film  is  very  carefully  washed 
and  then  coated  with  some  preservative  agent,  as  it  is  called, 
such  as  albumen,  tannic  acid,  gelatine,  honey,  syrup,  infusion 
of  malt,  glucose,  etc.,  and  then  when  otherwise  properly  pre- 
pared and  dry,  it  will  yield,  when  exposed  and  afterward  sub- 
jected to  the  action  of  a  reducing  agent,  an  intense  picture. 
I  say  the  rationale  of  this  phenomenon  is  still  a  problem. 
Some  suppose  that  the  albuminous,  collodio-albuminous,  gela- 
tinous, etc.,  film  becomes  permeable  to  the  developer  in  the 
dry  process ;  whilst  the  collodion  film  in  its  simple  unpre- 
served  condition  is  not  so.  Such  a  supposition  is,  however, 
the  mere  admission  of  our  inability  to  render  any  satisfactory 
explanation ;  it  is  the  admission  of  little  more  than  the  fact 
itself. 

As  yet,  also,  it  is  difficult  to  say  which  of  the  dry  pro- 
cesses in  vogue  is  absolutely  the  best ;  although  perhaps  the 
majority  would  throw  the  weight  of  their  opinion  into  the 
scale  of  the  Tannin  Process  of  Major  Russell.  The  dry  pro- 
cesses most  conspicuously  on  the  carpet  are  :  the  Albumen 
Process  /  the  Collodio- Albumen  or  Taupenot  Process  /  the 
Gelatine  or  Dr.  Hill  JVbrris's  Process  ;  the  Tannin  Process 
of  Major  Pussell  /  and  the  Resin  Process. 

The  Albumen  Process. 
This  process  was  in  use  several  years  before  that  of  collo- 
dion ;  Niepce  de  St.  Victor  first  produced  negatives  with  it. 
It  is  still  employed  by  some  of  the  most  distinguished  artists 
in  Europe  in  the'  production  of  stereographs,  both  negative 
and  positive,  also  of  photographs  of  interiors,  and  in  general 
of  pictures  of  still  life.  Its  theory  is  very  simple ;  but  its 
manipulation  demands  great  care  and  skill. 

Formula  for  Iodized  Albumen. 

The  white  of  egg,  10  ounces, 

Iodide  of  ammonium,  44  grains. 

Distilled  water,  (sufficient  to  dissolve  the  iodide.) 


234 


DRY  COLLODION  PROCESS. 


Dissolve  the  iodide  in  the  water,  then  add  the  solution  by 
degrees  to  the  white  of  egg,  entirely  freed  from  the  germ 
and  yolk,  and  beat  the  egg  up  well  with  a  wooden  spatula 
until  it  is  completely  converted  into  froth.  This  operation 
must  be  performed  in  a  place  as  perfectly  free  from  dust  as 
possible ;  and  then  the  albuminous  mixture  is  covered  with 
a  clean  sheet  of  paper  and  put  aside  to  settle  for  a  number 
of  hours.  After  standing  the  required  time,  the  surface  be- 
comes covered  with  a  sort  of  incrustation,  through  which  an 
aperture  is  made  to  allow  the  iodized  albumen  to  flow  out. 
In  some  formulas  for  iodizing  the  albumen,  a  bromide  is 
used  and  a  small  quantity  of  free  iodine. 


Distilled  water,  (sufficient  to  dissolve  the  salts.) 

Beat  up  the  white  of  egg  as  before.  The  operation  is  best 
performed  when  the  temperature  of  the  room  is  low.  A  few 
hours  previous  to  the  operation  of  coating  the  plates,  mop 
the  floor  and  wipe  all  the  shelves  with  a  damp  cloth  —  the 
great  difficulty  in  this  process  is  the  deposition  of  dust  or 
fibers  on  the  glasses  during  the  time  they  are  drying.  An- 
other trouble  (and  these  are  about  all  the  difficulties  the 
operator  has  to  contend  against)  is  the  flowing  of  the  plate 
with  an  even  and  uniform  film,  and  its  uniform  retention  on 
the  plate  until  dry.  The  plates,  of  course,  must  be  perfectly 
clean  in  this  process,  as  in  every  other  for  negative  pur- 
poses. 

Several  methods  have  been  proposed  by  which  the  plate 
can  be  covered  with  albumen,  most  of  which,  no  doubt,  have 
deterred  photographers  from  undertaking  this  branch.  I 
believe  the  best  method  is  to  flow  the  plate  exactly  as  you 
would  cover  it  with  collodion  ;  and  if  the  albumen  ceases  to 
flow  in  certain  parts,  to  use  a  glass  triangle  and  thus  scrape 
it  as  it  were  over  those  parts.  It  is  necessary  in  all  cases  to 
pour  upon  the  plate  much  more  albumen  than  you  would 
collodion,  in  order  to  cover  the  plates  easily  and  effectually ; 
most  of  the  superfluous  quantity  is  poured  off  at  the  right 
nearest  corner ;  whilst  the  residual  surplus  is  made  to  tra- 
verse the  plate  diagonally  to  the  farthest  left  corner  and 
then  flow  off  into  the  receiving  vessel.  If  any  surplus  still 
remains  it  is  flowed  gently  toward  the  middle  of  the  plate 


Formula  No.  2. 


The  white  of  egg, 
Iodide  of  potassium, 
Bromide  of  potassium, 
Free  iodine,  .    .  . 


10  ounces. 
44  grains. 
15  grains. 
2  grains. 


DRY  COLLODION  PROCESS.  285 

and  equalized  as  much  as  possible  over  the  whole  surface. 
The  next  operation  is  the 

Drying  Process. 

This  operation,  in  general,  has  been  rendered  very  tedious 
and  inefficient ;  the  plates  were  allowed  to  dry  spontaneous- 
ly, which  occupied  several  hours,  and  in  the  mean  while  the 
albumen  film  became  contaminated  with  the  deposition  of 
dust,  which  completely  spoiled  the  plates.  By  the  following 
method  they  may  be  dried  in  a  few  minutes.  Pre'pare  a  me- 
tallic table,  that  is,  a  plate  of  iron  or  other  metal  supported 
on  three  legs,  sufficiently  capacious  for  the  purpose.  Be- 
neath this  an  alcohol  lamp  is  kept  burning,  by  which  the 
plate  is  maintained  at  any  given  temperature  by  the  adjust- 
ment of  the  wick,  or  its  distance  from  the  plate.  Next,  sup- 
posing that  stereoscopic  negatives  are  the  objects  of  manipu- 
lation, prepare  a  piece  of  brass  or  iron  longer  and  wider  than 
the  stereoscopic  plate  by  a  quarter  of  an  inch ;  cut  out  from 
this  a  piece  of  the  same  shape  as  the  negative  plate,  but 
shorter  in  its  two  dimensions  by  a  quarter  of  an  inch.  On 
one  end  rivet  a  metallic  handle,  which  may  be  fixed  into  a 
wooden  one.  Turn  up  a  ledge  on  either  side,  as  also  on 
either  end,  (as  far  as  practicable  on  the  nearer  end  by  rea- 
son of  the  handle,)  about  one  tenth  of  an  inch  high.  It  is 
evident  that  so  constructed,  the  negative  can  lie  on  this 
skeleton  plate  and  within  the  ledges.  Place  the  plate,  al- 
bumenized  as  above,  on  this  metallic  plate,  and,  taking  hold 
of  the  handle  with  the  right  hand,  bring  it  into  a  horizontal 
position  over  the  heated  plate  at  a  proper  distance  above  it ; 
equalize  the  albumen  by  inclining  the  hand  as  required ; 
and,  keeping  the  hand  in  continual  motion,  the  film  will  soon 
dry  uniformly,  and  the  plate  can  then  be  put  away  for  future 
use.    So  prepared  it  will  keep  for  an  indefinite  time. 

Sensitizing  the  Film. 

An  oblong  flat  porcelain  or  glass  dish  is  preferred  to  the 
vertical  bath  for  the  purpose  of  sensitizing  the  film ;  and  if 
the  dish  be  made  twice  as  long  as  required,  it  will  answer 
the  purpose  best. 

Formula  for  the  Sensitizing  Solution. 


Nitrate  of  silver,   1  ounce. 

Acetic  acid,   5  ounces. 

Distilled  water,   10  ounces. 

Iodide  of  potassium   2  grains. 

12 


236 


DRY  COLLODION  PROCESS. 


Lay  the  albumen  plate  along  one  side  of  the  glass  dish ;  then 
raising  this  side,  pour  into  the  inclined  side  a  sufficient 
quantity  of  the  bath  ;  with  a  dexterous  move  raise  the  in- 
clined side  so  that  the  fluid  may  flow  over  the  albumen  film 
in  one  quick  continuous  layer.  By  this  contrivance  all  lines 
or  marks  of  stoppage  are  avoided.  This  is  a  very  necessary 
provision  here  ;  for  the  slightest  hesitation  or  stoppage  wrill 
infallibly  show  its  effect  on  the  negative.  About  half  a  min- 
ute will  be  sufficient  to  coagulate  the  albumen,  and  to  sensi- 
tize the  film.  This  operation  is  performed  in  the  dark-room ; 
whereas  that  of  albumenizing  takes  place  in  diffused  light. 
After  sensitization  —  which  occupies  from  thirty  to  fifty 
seconds — the  plate  is  removed  from  the  bath  by  raising  it 
first  with  a  bent  silver  hook,  and  then  seizing  it  by  one 
corner  with  the  hand.  It  is  then  washed  under  the  tap  and 
left  to  soak  in  a  dish  of  distilled  water  until  the  next  plate  is 
prepared.  Finally,  when  it  is  supposed  the  free  nitrate  of 
silver  has  been  thoroughly  removed,,  it  is  used  immediately 
or  dried  for  future  use.  The  quantity  of  acetic  acid  in  the 
above  formula  may  be  diminished  in  many  instances ;  its  ob- 
ject is  to  prevent  fogging,  but  it  diminishes  sensitiveness  at 
the  same  time.  If  with  half  the  quantity  no  fogginess  super 
venes,  this  quantity  will  be  quite  enough ;  by  thus  beginning 
with  a  small  amount  of  acetic  acid,  and  gradually  increasing 
until  fogging  ceases,  more  rapid  effects  may  be  obtained  in 
the  exposure.  When  the  plates  are  kept  long  they  undergo 
a  species  of  decomposition  which  induces  fogginess ;  the 
fresh  plates,  therefore,  are  in  the  best  condition  for  produc- 
ing normal  results  with  the  greatest  rapidity,  because  the 
sensitizing  bath  requires  the  least  amount  of  acid. 

Blisters  are  apt  to  arise  in  the  film  by  immersion  in  the 
sensitizing  bath,  or  during  the  subsequent  operations.  These 
are  frequently  owing  to  the  imperfect  cleaning  of  the  plates 
or  in  the  clumsy  flowing  of  the  albumen.  Gummy  substances 
are  sometimes  added  to  the  albumen  in  order  to  render  it 
more  adherent  or  less  contractile. 

Exposure  in  the  Camera. 
The  amount  of  exposure  will  depend  on  the  conditions  of 
the  light,  the  focal  length  of  the  lens,  and  the  sensitiveness 
of  the  albumen.  In  the  bright  light  of  spring  an  exposure 
of  two  or  three  minutes  with  a  pair  of  stereoscopic  lenses 
will  in  general  be  amply  sufficient.  Experience  alone  can 
determine  the  amount  of  time  required  in  a  given  case. 


DRY  COLLODION  PROCESS. 


237 


Development  of  the  Image. 
The  plate  is  placed  in  a  glass  dish,  or  in  one  of  gutta- 
percha, and  the  developer  is  poured  upon  it  by  the  same 
mode  of  manipulation  as  just  described  to  be  used  in  the 
sensitizing  operation. 

Formula  for  the  Developing  Solution. 

Gallic  acid,  8  grains. 

Distilled  water,  (warm,  90°,)  2  ounces. 

Previous  to  immersion  in  the  above  solution  the  plates  are 
subjected  to  the  softening  action  of  a  warm  dilute  solution 
of  gallic,  acid  (one  grain  to  the  ounce  of  distilled  water)  for 
half  an  hour.  After  this  the  plate  is  flowed  with  a  sufficient 
quantity  of  the  above  solution  containing  five  or  six  drops 
of  a  solution  of  nitrate  of  silver  two  per  cent  strong.  The 
image  will  soon  begin  to  appear,  and  will  proceed  until  the 
vigor  of  the  print  is  satisfactory.  The  development  is  not 
so  soon  complete  as  in  collodion  operations,  the  time  required 
varying  from  a  few  minutes  to  forty  minutes  or  an  hour. 
Any  amount  of  exposure  almost  can  be  made  to  yield  a  good 
picture  By  adapting  the  developing  solution  in  accordance 
with  the  exposure.  If  the  plate  has  been  under-exposed 
more  silver  will  have  to  be  used ;  if  over-exposed,  less  will 
be  found  to  be  all  that  is  necessary.  Silver  from  the  sensi- 
tizing bath  might  be  used,  but  in  this  case  it  must  contain 
more  acetic  acid.  The  Aveak  solution  above  described  is  to 
be  preferred ;  and  if  there  is  a  tendency  to  fogging,  add  a 
few  drops  of  acetic  acid  to  counteract  the  effect.  As  soon 
as  the  shades  are  sufficiently  dense,  the  plate  is  removed  from 
the  bath,  well  washed  in  many  waters,  and  then  the  image 
is  fixed  in  a  solution  of  hyposulphite  of  soda.  No  varnish- 
ing is  required,  because  the  albumen  film  is  quite  hard  of 
itself. 

Taupenot  Process —  Collodio- Albumen  Process. 
This  process  was  originally  proposed  by  Taupenot.  His 
design  was  to  combine  the  advantages  of  these  two  ingre- 
dients, albumen  and  collodion.  The  collodion  film  on  the 
glass  is  a  much  better  receptacle  of  the  albumen  than  the 
glass  itself ;  but  the  operation  is  somewhat  circuitous,  inas- 
much as  the  plate  is  sensitized  twice.  Other  methods  have 
since  been  devised,  in  which  the  collodio-albvminous  film  re- 
quires but  one  sensitization.  Some  of  these  are  found  to  be 
very  effectual  dry  processes. 


238 


DRY  COLLODION  PROCESS. 


Preparation  of  the  Glass  Plates. 
These  are  first  immersed  for  a  number  of  hours  in  the  fol- 
lowing solution  : 

Salts  of  tartar,    .  1  ounce. 

Kain-water,   16  ounces. 

If  the  plates  have  been  already  employed  before,  soak  them 
in  water  and  remove  the  collodion  film  with  a  piece  of  rag. 
The  alkaline  solution  can  be  used  several  times.  As  soon  as 
the  plates  are  removed  from  this  solution,  pass  them  through 
water  several  times,  and  then  clean  and  polish  them  in  the 
vice,  by  means  of  alcohol  and  rotten  stone,  as  previously  di- 
rected. Immediately  before  the  collodion  is  flowed  upon  the 
plate,  it  is  dusted  with  a  silk  cloth,  and  then  with  the  broad 
camel's  hair  pencil.  A  collodion  that  flows  well  and  one 
that  adheres  forcibly  to  the  glass  is  to  be  preferred. 

Formula  for  the  Collodion. 


Ether,  (concentrated,)  12  ounces. 

Alcohol,       "   3.  ounces. 

Pyroxyline,  1  drachm. 

Iodide  of  ammonium,   1  drachm. 

Bromide  of  ammonium,  15  grains. 


This  collodion,  containing  quite  an  excess  of  ether,  which 
is  very  volatile,  has  to  be  poured  over  the  plate  w^ith  great 
dexterity.  It  is  very  fluid  and  admits  of  this  dexterity.  The 
plate  is  then,  as  soon  as  the  film  has  sufficiently  congealed, 
immersed  in  the  ordinary  nitrate  of  silver  batfr>  containing 
about  35  grains  of  the  nitrate  to  the  ounce  of  distilled  water. 
It  is  left  in  this  bath  for  four  or  five  minutes  and  then  taken 
out  and  allowed  to  drain.  After  this  proceeding,  the  plate 
is  immersed  in  a  dish  of  rain-water  and  well  washed  by  agi- 
tation, or  it  may  be  washed  at  the  tap  in  the  ordinary  meth- 
od, and  then  flowed  with  distilled  water  several  times,  and 
again  allowed  to  drain.  It  is  next  flowed,  while  still  moist, 
with  the  following  albuminous  preparation  : 


The  white  of  egg,  (free  from  germs  and  yolk,)        12  ounces. 

Distilled  water,  2  ounces. 

Iodide  of  ammonium,  44  grains. 

Bromide  of  ammonium,  16  grains. 

Ammonia,  1  ounce. 

White  sugar,  2  drachms. 


These  ingredients  are  intimately  mixed  by  an  egg-beater 
until  the  mass  is  reduced  to  froth.  They  are  then  allowed 
to  subside  for  a  day  or  two.  The  clear  part  is  separated  by 
decantation  or  by  a  syringe  from  the  residue  below,  and  from 


DRY  COLLODION  PROCESS. 


239 


the  indurated  scum  on  its  surface  above.  With  this  clear  so- 
lution flow  the  still  moist  plate  as  you  would  with  collodion 
almost.  Holding  the  plate  by  the  left-hand  nearer  corner, 
between  the  thumb  and  the  first  finger,  pour  the  albumen  on 
the  right-hand  further  corner,  then  inclining  the  plate,  let  the 
albumen  flow  to  the  left-hand  further  corner.  Now  allow  the 
whole  body  of  the  albumen  to  flow  down  in  one  mass,  driv- 
ing the  water  before  it  until  it  arrives  at  the  nearest  edge. 
Inclining  the  right-hand  nearest  corner,  allow  the  water  to 
flow  off  together  with  the  excess  or  surplus  of  the  albumen 
into  a  separate  receiver.  Now  raise  the  nearest  edge  of  the 
plate  and  let  the  surplus  proceed  back  again  to  its  place  of 
starting,  and  once  more  to  the  nearest  right-hand  corner, 
when  all  excess  is  allowed  to  flow  off.  The  plates  are  then 
reared  away  on  one  corner  to  dry.  In  this  state  the  film  is 
not  sensitive,  and  consequently  the  plates  so  far  can  be  pre- 
pared beforehand  and  preserved  until  wanted. 

Sensitizing  of  the  Taupenot  Plates. 

Nitrate  of  silver,  1  ounce. 

Acetic  acid,  1  ounce. 

Nitrate  of  silver,   12  ounces. 

The  plates  are  immersed  in  this  bath  with  great  care  and 
dexterity,  in  order  to  avoid  all  lines  of  stoppage,  etc.  In 
thirty  seconds  the  film  will  be  sufficiently  sensitized.  The 
plate  is  then  taken  out  and  plunged  into  a  dish  of  wrater, 
moved  about  in  this,  then  transferred  to  another,  allowed  to 
drain,  finally  flowed  two  or  three  times  with  distilled  water, 
and  put  away  to  dry  in  a  perfectly  dark  place. 

In  this  condition  the  film  is  much  more  sensitive  to  light 
than  albumen  alone,  although  it  is  less  so  than  collodion.  The 
plates  can  be  preserved  sensitive  for  several  months,  but  the 
sensitiveness  gradually  deteriorates  by  age. 

Exposure. 

With  a  portrait  combination  an  exposure  of  two  or  three 
seconds  will  be  found  to  be  sufficient  to  receive  a  good  im 
pression  of  an  object  well  illumined  by  the  sun,  and  as  many 
minutes  will  suffice  with  a  single  lense. 

Development  of  the  Image. 
The  developing  solution  is  composed  as  follows  : 

Distilled  water,  12  ounces. 

Gallic  acid,   18  grains. 

Pyrogallic  acid,   6  grains. 

Alcohol,  2  drachms. 

Acetic  acid,  \  drachm. 


240 


DRY  COLLODION  PKOOESS. 


To  every  three  ounces  of  this  solution  add  a  solution  of 
one  grain  of  nitrate  of  silver,  when  about  to  use  it.  A  larger 
proportion  of  pyrogallic  acid  and  nitrate  of  silver  will  in- 
crease the  intensity  of  the  blacks  ;  and  where  the  time  of  ex- 
posure has  been  too  long,  the  gallic  acid  may  be  diminished 
and  the  acetic  acid  increased.  The  horizontal  bath  is  pref- 
erable for  this  sort  of  development.  The  plate,  first  dipped 
in  water,  is  then  lowered  dexterously  with  the  collodio-al- 
bumen  surface  downward  into  the  solution,  and  the  upper 
end  is  allowed  to  rest  on  a  piece  of  glass  or  porcelain,  to  pre- 
vent the  film  from  coming  in  contact  with  the  bottom  of  the 
vessel.  The  plate  is  raised  from  time  to  time  to  watch  the 
progress  of  the  development,  which  may  occupy  from  ten 
minutes  to  twenty-four  hours.  "When  the  shades  are  intense 
enough,  the  plate  is  taken  out,  well  washed,  and  then  im- 
mersed in  the  fixing  solution. 

Fixation  of  the  Taupenot  Plates. 

Hyposulphite  of  soda,  1  ounce. 

Water,  20  ounces. 

Even  a  wreaker  solution  will  frequently  be  all  that  is  re- 
quired. The  soluble  iodides  being  removed,  the  plates  are 
taken  out  and  thoroughly  washed  as  usual. 

Modified  Albumen  Process.    [By  James  Larpey.) 

Let  the  plates  be  coated  with  any  collodion,  iodized  or 
non-iodized,  and  afterward  well  washed. 

Flow  them  with  the  albumenizing  solution,  which  is  made 
as  follows : 

Formula  for  Iodized  Albumen. 


Albumen,   10  ounces. 

Iodide  of  ammonium,   50  grains. 

Bromide  of  potassium,  .   12  grains. 

Water,   2|  ounces. 


The  mode  of  flowing  is  the  same  as  already  described  for 
the  Taupenot  process.  After  draining,  dry  as  before  indi- 
cated. 

Sensitizing  Solution. 

Nitrate  of  silver,  60  grains. 

Acetic  acid,  60  minims. 

Water,  1  ounce. 

The  time  required  will  be  thirty  seconds  or  thereabouts ; 
emove  from  the  bath  and  wash  thoroughly. 


DRY  COLLODION  PROCESS. 


241 


Exposure. 

This  preparation  requires  about  twice  as  long  an  exposure 
as  wet  collodion. 

Developer. 

Saturated  solution  of  gallic  acid  and  a  few  drops  of  a  so- 
lution of  nitrate  of  silver,  (fifty  grains  to  the  ounce  of  water.) 
By  varying  the  quantity  of  nitrate,  any  kind  of  tone  can  be 
got.  A  small  quantity  yields  brown  tones  ;  a  larger  quantity 
black  tones. 

Fixing. 

Wash  thoroughly  and  then  fix  in  the  ordinary  solution  of 
hyposulphite  of  soda ;  finally  wash  and  dry. 

The  collodion  film  in  this  process  facilitates  the  flowing  of 
the  albumen,  which  besides  dries  much  quicker.  Its  keeping 
properties  are  very  good. 

Modified  Collodio- Albumen  Process.     {By  James  Mudd.) 

Coat  the  plates  with  collodion,  as  usual.  As  soon  as  the 
film  is  sufficiently  adhesive,  immerse  in  the  ordinary  bath  of 
nitrate  of  silver.  Dilute  the  collodion  with  ether  if  it  gives 
a  very  thick  and  creamy  film.  After  sensitizing,  wash  the 
plates  thoroughly,  and  then  immerse  them  in  a  weak  solu- 
tion of  iodide  of  potassium,  (one  grain  to  the  ounce  of  water,) 
for  two  or  three  minutes,  moving  them  gently  all  the  while. 
Wash  again  and  allow  to  drain  for  one  minute. 

Formida  for  Iodized  Albumen. 


Albumen,   10  ounces. 

Iodide  of  potassium,  50  grains. 

Bromide  of  potassium,  10  grains. 

Ammonia,   100  minims. 

Water,      .       ...   2£  ounces. 


First  dissolve  the  iodide  and  bromide  in  the  water,  then 
add  the  ammonia ;  mix  this  solution  with  the  albumen,  and 
beat  the  whole  into  a  froth,  and  then  allow  it  to  settle  for  at 
least  twenty-four  hours.  Decant,  as  previously  directed,  be- 
fore use.  While  the  plate  is  still  wet,  pour  on  the  albumen. 
Pour  it  on  and  off  twice.  Allow  the  plate  to  drain  for  a  few 
minutes  ;  then  dry  it  rapidly  before  a  clear  fire,  and  make  it 
quite  hot. 

Sensitizing  Solution. 

Nitrate  of  silver,   40  grains. 

Glacial  acetic  acid,  £  drachm. 

Distilled  water,  1  ounce. 


242 


DRY  COLLODION  PROCESS. 


Warm  the  plate  slightly,  and  then  immerse  it  in  this  solu* 
tion ;  drain  for  a  moment,  and  wash  in  different  dishes  of 
pure  water,  and  finally  under  the  tap.  Dry  the  plates  by 
artificial  heat,  or  let  them  dry  spontaneously. 

Plates  so  treated  are  very  sensitive,  and  possess  tolerable 
keeping  properties.  In  summer,  however,  it  is  advisable  to 
prepare  fresh  ones  every  two  weeks  or  so. 

Development. 

The  plate,  first  moistened  and  supported  on  a  horizontal 
stand,  pour  upon  it  a  fresh  solution  of  pyrogallic  acid,  (three 
grains  to  the  ounce  of  water.)  The  image  will  soon  appear, 
but  it  requires  intensity. 

Intensifying. 

Pyrogallic  acid,  2  grains. 

Citric  acid,  2  grains. 

Nitrate  of  silver  solution,  (20  gr.  strong,)    2  or  3  drops. 

Pour  a  sufficient  quantity  of  the  above  upon  the  plate  and 
keep  it  in  motion.  If  the  shades  do  not  assume  sufficient  in- 
tensity, use  more  silver.  The  solution  may  be  warm  in  cold 
weather,  or  when  the  picture  has  been  under-exposed. 

Fixing  Solution. 

Hyposulphite  of  soda,  6  ounces. 

Water,  16  ounces. 

Wash  the  plates  well  before  immersion ;  fix  as  usual,  and 
again  wash.  Cyanide  of  potassium  must  not  be  used  for  this 
purpose. 

Fothergill  Process. 
This  process,  like  the  two  preceding,  is  a  mere  modifica- 
tion of  the  Taupenot  process,  the  principal  difference  be- 
tween this  and  the  Taupenot  being  that  the  plate  is  sensi- 
tized only  once.  The  plate  is  first  flowed  as  usual  with  any 
ripe  bromo-iodized  collodion,  and  then  as  usual  sensitized  in 
the  common  nitrate  of  silver  bath ;  after  removal  from  the 
bath,  soak  the  plates  in  distilled  or  rain-water,  so  as  to  re- 
move all  but  a  mere  trace  of  nitrate  of  silver.  This  part  of 
the  operation  is  probably  the  most  important  and  character- 
istic of  the  operation.  Some  pursue  the  plan  of  soaking  the 
plates,  as  just  directed,  in  a  dish  of  distilled  water,  keeping 
the  water  moving  over  their  surface  until  all  apparent  oily 
streaks  or  greasiness  have  disappeared.  Others  recommend 
a  more  definite  plan.  They  use  a  measured  quantity  of  dis- 
tilled or  rain-water  for  a  certain  number  of  square  inches  of 
surface.  ■  For  a  stereoscopic  plate  half  an  ounce  of  water  b 


DRY  COLLODION  PROCESS. 


243 


poured  carefully  on  one  corner  of  the  plate,  and  is  made  to 
cover  the  whole  quickly,  as  in  the  developing  process.  The 
water  is  then  kept  in  motion  by  tilting  the  plate  slightly  up 
and  down,  until  the  greasiness  disappears  ;  it  is  then  poured 
off*,  and  the  plate  is  allowed  to  drain  for  a  moment,  and  cov- 
ered with  the  following  preservative  solution  : 

Albumen,   .2  ounces. 

Ammonia,  20  minims. 

Water,       .    .   6  ounces. 

Mix  well  by  agitation  in  a  large  bottle,  and  filter  through  a 
sponge  immediately  before  use. 

This  solution  is  poured  upon  each  plate  whilst  still  moist, 
in  the  same  manner  as  plates  are  covered  with  collodion ;  the 
residual  quantity  is  poured  off  at  one  of  the  near  corners. 
Another  quantity  of  the  albumen  is  now  poured  upon  the 
plate  and  allowed  to  remain  one  minute,  after  which  it  is 
poured  off,  and  the  plate  is  properly  washed,  drained,  and 
dried  either  spontaneously  or  by  the  application  of  heat. 

Developing  Solution. 
After  exposure,  the  plates  are  first  moistened  in  distilled 
water,  and  then  covered  with  the  following  developer : 

Pyrogallic  acid,  3  grains. 


Add  to  each  ounce  of  the  above  solution  half  a  drachm  of 
a  solution  of  nitrate  of  silver,  containing  fifteen  grains  to  the 
ounce  of  water.    Wash  thoroughly  when  the  image  is  per- 


Fixing  Solutior,. 
Fix  the  impressions  in  a  bath  of  hyposulphite  of  soda ; 
wash,  dry,  and  varnish. 


Citric  acid, 
Water,  .  , 
Alcohol,  . 


1  grain. 

2  ounces. 
10  minims. 


feet. 


CHAPTER  XXXVII. 


DR.  HILL  MORRIS'S  PROCESS — GELATINE  PROCESS. 

Make  use  of  a  non-contractile  bromo-iodjized  collodion,  and 
after  the  film  has  been  sensitized  in  the  ordinary  nitrate  of 
silver  bath,  and  allowed  to  drain,  pour  upon  it  a  solution  of 
honey,  containing  one  ounce  of  honey  to  two  ounces  of  dis- 
tilled water.  The  solution  must  be  warmed  and  filtered 
through  filtering  paper,  previous  to  its  application.  This 
solution  may  be  kept  in  vials,  completely  filled,  for  a  con- 
siderable time.  As  soon  as  the  plate  has  been  thoroughly 
covered  with  the  syrup,  it  is  very  carefully  washed  beneath 
the  tap,  until  the  washings  no  longer  taste  either  of  honey 
or  silver.  The  plate  is  next  flowed  with  the  following  solu- 
tion : 

Preservative  Solution. 

Gelatine,   1  drachm. 

Waiter,  (distilled,)   20  ounces. 

Alcohol,  ...   4  drachms. 

Soak  the  gelatine  in  the  water  until  it  has  swelled,  then  ap- 
ply heat  to  dissolve  it.  After  it  is  cool,  mix  with  the  solution 
the  white  of  an  egg  very  intimately,  then  boil  the  mixture, 
so  as  to  coagulate  the  albumen.  Let  it  stand  for  a  few  mo- 
ments, and  then  filter  whilst  still  hot  through  a  flannel  bag 
before  a  fire.  The  first  portions  of  the  filtrate,  not  being 
clear,  are  poured  back  again  into  the  funnel  and  again  fil- 
tered. The  alcohol  is  next  added  to  the  clear  solution,  in 
order  to  communicate  to  it  keeping  properties. 

When  about  to  use  the  gelatine,  place  the  bottle  that  con- 
tains it  in  a  dish  of  hot  water,  in  order  that  the  gelatine  may 
melt ;  a  separate  vessel  used  for  flowing  the  mixture  is  nearly 
filled  with  the  melted  gelatine,  and  rendered  still  more  hot 
and  fluid  in  a  hot-water  bath.  The  plate  is  first  heated  and 
then  flowed  with  this  hot  solution,  which  is  allowed  to  rest 
upon  the  surface  a  moment ;  fresh  gelatine  is  then  poured 
upon  the  plate,  and  off  again  at  one  corner,  until  the  film  is 
quite  uniform.    Drain  the  plate  and  dry. 


DR.  HILL  NORRIS'S  PROCESS. 


245 


The  exposure,  developing,  and  fixing  are  the  same  as  in 
the  preceding  processes. 

Dr.  Hill  Norris's  theory  of  this  process  is  as  follows  :  The 
collodion  film,  as  long  as  it  is  moist,  is  a  porous  material,  and 
when  it  is  once  dried,  it  ceases  to  be  porous.  Now,  by 
the  use  of  honey,  gelatine,  etc.,  on  the  moist  surface,  it  is 
supposed  that  these  substances  penetrate  the  pores,  and  thus 
prevent  the  pyroxyline,  during  induration  and  drying,  from 
closing  up  apertures  which  allow  the  developing  solution  to 
permeate  the  film.  The  special  function  of  the  honey,  how- 
ever, seems  to  be  the  removal  of  every  trace  of  nitrate  of  sil- 
ver. 

Tannin  Process  of  Major  Russell. 

This  process  promises  to  supersede  most  of  the  preceding 
dry  methods.  The  collodion  is  apt  to  wrinkle  or  slide  en- 
tirely from  the  plate,  when  prepared  according  to  the  origin- 
al mode.  There  are,  therefore,  two  methods  of  preparing 
the  glass  for  the  reception  of  the  collodion  film. 

In  the  first  place,  and  in  all  cases,  file  the  edges  on  both 
sides  of  each  plate.  Then,  if  the  plate  is  not  first  to  be  covered 
with  a  solution  of  gelatine,  place  it  upon  a  flat  surface,  as  on 
the  corner  of  a  table,  and  laying  a  flat  ruler  along  either  side, 
leaving  one  eighth  of  an  inch  between  the  edge  of  the  glass 
and  the  edge  of  the  ruler,  abrade  the  surface  of  the  glass 
along  this  narrow  strip  by  means  of  a  wet  emery  or  corun- 
dum grindstone,  such  as  is  used  by  dentists.  In  tnis  way  a 
rough  border  will  be  made  all  round,  to  which  the  collodion 
will  adhere  with  great  tenacity. 

The  plates  must  be  exceedingly  well  cleaned  and  free  from 
all  sorts  of  reduction  from  previous  use.  So  prepared,  they 
may  be  manipulated  without  much  risk  of  undergoing  the 
troubles  alluded  to.  But  it  is  the  opinion  of  many  good 
amateurs  in  this  department,  that  the  plates  work  much  bet- 
ter when  previously  covered  with  a  coating  of  gelatine,  which 
acts  not  alone  as  a  preventive  to  wrinkles,  etc.,  in  the  collo- 
dion film,  but  is  supposed  in  some  way  to  ameliorate  the 
photographic  results  during  development,  with  all  sorts  of 
collodion.  Small  plates  need  scarcely  to  be  covered  with 
gelatine. 

Gelatine  Operation. 
To  prepare  a  clear  solution  of  gelatine,  proceed  as  follows  : 
Formula. 

Gelatine,  30  grains. 

Acetic  acid,  (glacial,)  6  minims. 

Water  distilled,  10  ounces. 


246 


DR.  HILL  NORRIS'S  PROCESS 


Immerse  the  gelatine  in  the  cold  water,  and  let  it  swell  for 
two  or  three  hours  in  a  warm  room ;  after  which  add  the 
acetic  acid,  and  apply  a  gentle  heat  until  the  gelatine  is  dis- 
solved.   To  this  add  the  following  solution : 

Alcohol,  6  drachms. 

Iodide  of  cadmium,  12  grains. 

Bromide  of  cadmium,  3  grains. 

Filter  the  solution  two  or  three  times  through  paper  in  a 
warm  place.  So  prepared,  it  will  keep  a  long  time,  is  limpid, 
and  has,  when  warm,  about  the  same  consistency  as  collo- 
dion, but  it  does  not  flow  over  the  plate  with  the  same  facil- 
ity. 

Warm  the  plates  and  the  gelatine  solution  ;  then  pour  the 
latter  upon  the  surface  of  the  former,  and  cause  it  to  spread, 
either  by  breathing  forcibly  upon  it  or  by  means  of  a  glass 
triangle.  The  surplus  quantity  is  poured  off  at  one  corner 
into  a  separate  vessel,  and  after  dripping,  the  plates  are  reared 
away  against  the  wall  on  the  same  corner,  upon  bibulous 
paper,  until  they  are  dry.  Spontaneous  drying  in  a  warm 
room  is  preferable  to  drying  quickly  by  artificial  heat.  The 
plates  so  prepared  can  be  preserved  when  dry  in  grooved 
boxes  for  an  indefinite  time. 

Collodion  for  the  Tannin  Process. 
A  good  bromo-iodized  collodion,  already  ripe,  and  of  a 
powdry  nature  is  the  best  for  this  process. 

Formula  for  Collodion. 


Iodide  of  ammonium,  16  grains. 

Iodide  of  cadmium,  8  grains. 

Bromide  of  cadmium,  16  grains. 

Pyroxyline,  48  grains. 

Alqphol,  spec,  grav.,  .805,   4  ounces. 

Ether,  concentrated,  4  ounces. 


After  the  plates  have  been  carefully  flowed  with  this  col- 
lodion, they  are  sensitized  in  a  bath  of  nitrate  of  silver,  made 
slightly  acid  with  acetic  acid,  that  is,  with  one  drop  of  the 
ordinary  acetic  acid  to  each  ounce  of  the  neutral  nitrate  of 
silver  bath.  For  instantaneous  work,  or,  properly  speaking 
here,  for  very  short  exposures,  a  neutral  bath  would  be 
the  most  appropriately  calculated  to  succeed.  When  the 
color  of  the  collodion  film  indicates  a  sufficiency  of  sensitiza- 
tion, which  will  be  in  four  or  five  minutes  under  ordinary 
circumstances,  the  plate  is  taken  out  and  immersed  in  a  dish 
of  distilled  water,  moved  about  for  a  short  time,  and  then 
left  collodion-film  upward  in  the  dish,  until  a  second  plate  is 


DR.  HILL  NORRIS'S  PROCESS. 


247 


collodionized  and  sensitized.  It  is  then  thoroughly  washed 
under  the  tap  with  common  water,  and  finally  flowed  with 
distilled  water. 

Preservative  Solution  of  Tannin. 
This  solution  may  vary  in  strength  from  ten  to  thirty  grains 
of  tannin  to  one  ounce  of  water,  depending  upon  the  light 
and  the  nature  of  the  collodion. 

Tannin,  15  grains. 

Distilled  water,  1  ounce. 

Dissolve  and  filter  through  paper  before  use,  and  then  add 
four  or  five  minims  of  alcohol  to  the  ounce  of  water,  but  al- 
ways after  filtration.  Of  this  solution  pour  first  a  small  quan- 
tity upon  the  plate,  so  as  to  remove  before  it  all  superfluous 
water ;  pour  it  on  and  off  two  or  three  times,  and  afterward 
commence  with  a  fresh  solution.  Allow  the  plate  to  drain 
for  a  minute  or  two,  then  rear  it  up  on  end  upon  a  piece  of 
blotting  paper,  and  afterward  dry  spontaneously  or  by  ar- 
tificial heat,  remote  from  all  light.  When  perfectly  dry,  the 
plates  will  keep  in  the  dark  for  a  long  time. 

When  the  contrasts  of  the  landscape  are  very  marked,  and 
the  light  brilliant,  a  less  quantity  of  tannin  may  be  used ;  the 
greater  the  quantity  of  tannin,  the  greater  the  density  of  the 
shades.  When  the  plates  are  dry,  the  film,  if  in  a  right  con- 
dition, will  be  bright  and  highly  polished  in  its  appearance. 

If  the  tannin  plates  have  not  first  been  covered  with  a  so- 
lution of  gelatine,  this  is  the  time,  before  they  are  put  away, 
to  proceed  round  the  edges  of  the  film  with  varnish.  This 
operation  can  be  performed  best  by  dipping  the  quill  end  of 
a  strong  feather  from  a  hen's  wing  into  the  varnish,  and  then, 
inclining  the  feather,  begin  at  one  corner  of  the  plate  in  con- 
tact with  the  edge  and  proceed  to  the  other  end  slowly,  so 
that  a  small  quantity  of  the  varnish  is  attracted  by  the  col- 
lodion film  as  you  advance.  The  side  of  the  quill  is  in  con- 
tact with  the  edge,  and  not  the  end.  As  soon  as  the  varnish 
is  thoroughly  dry,  the  plates  are  stored  away.  It  is  best  to 
use  the  plates  as  soon  after  preparation  as  possible. 

The  time  of  exposure  is  three  or  four  times  as  long  as  with 
the  wet  process,  but  this  may  be  shortened  by  following  the 
plan  of  development  recommended  by  Dr.  Draper. 

Development. 

«   ,      (  Pyrogallic  acid,  72  grains. 

*0,  *     (  Alcohol,  1  fluid  ounce. 

Filter  if  there  is  any  turbidity,  otherwise  not. 


248 


DR.  HILL  KOBRIS'S  PROCESS. 


-  (  Nitrate  of  silver,   20  grains. 

No.  2.    -j  Citric  acid,  20  grains. 

(  Distilled  water,  1  ounce. 

Filter  if  there  is  a  white  precipitate,  otherwise  not.  Witfc 
No.  1  and  No.  2  as  stock  bottles,  proceed  as  follows  : 

Dilute  solution  of  (  Solution  No.  1,  .    .    .    1  drachm.  )  ^ 

No.  1.         \  Distilled  water,    .    .    .  C  ounces.  \ For  Present  use' 

Of  this  dilute  solution  of  No.  1,  take  out  four  drachms  for  a 
stereoscopic  slide,  and  add  to  it  from  fifteen  to  twenty-five 
minims  of  No.  2.  This  mixture  is  made  immediately  before 
the  plate  is  to  be  developed. 

Immerse  the  dry  plate  for  a  few  seconds  in  distilled  water ; 
then  pour  on  the  developer  and  keep  it  in  motion  until  the 
image  appears.  If  the  picture  is  slow  in  making  its  appear- 
ance, although  the  sky  develops  quickly,  the  time  of  exposure 
was  too  short,  and  the  developer  must  be  increased  in  strength, 
by  adding  ten  or  fifteen  drops  of  No.  1.  On  the  contrary, 
where  the  time  has  been  too  long,  the  development  on  all 
parts  will  be  simultaneous,  and  the  proper  equilibrium  of  ac- 
tion will  have  to  be  maintained  by  adding  a  few  drops  of  No. 
2,  otherwise  the  sky  will  not  be  opaque  enough. 

Dr.  Draper's  modification  consists  in  immersing  the  plates 
after  exposure  in  a  vessel  of  hot  distilled  water,  and  then 
proceeding  as  above.  The  development  is  very  rapid.  In 
consequence  of  this  the  time  of  exposure  can  be  reduced  al- 
most to  instantaneity. 

It  is  advisable  not  to  postpone  the  development  long  after 
the  exposure  ;  during  the  evening  of  the  day  on  which  the 
pictures  were  taken  is  in  all  respects  an  appropriate  time  for 
the  development,  and  although  in  many  instances  this  opera- 
tion can  be  put  off,  it  is  not  advisable.  The  color  of  the 
image  by  the  tannin  process  is  rich  and  warm  ;  its  tone  is 
very  agreeable.  Plates  prepared  either  by  this  process  or 
by  the  albumen  are  well  adapted  for  taking  transparent  pos- 
itives, by  direct  contact  printing,  for  the  magic  lantern,  or 
for  the  stereoscope. 

The  developed  plates  are  well  washed  and  fixed  in  a  bath 
of  hyposulphite  of  soda,  but  not  of  the  cyanide,  because  it  is 
apt  to  loosen  the  film.  They  are  then  carefully  washed,  so 
as  not  to  disturb  the  film,  dried  and  varnished. 

The  Tannin  and  Honey  Process. 
Several  modifications  of  the  Tannin  process  have  been  pro- 
posed, more  or  less  successful ;  the  honey  process  of  Mr.  Eng- 
land being  one  which  seems  to  possess  considerable  advan- 


DR.  HILL  NORRIS'S  PROCESS. 


249 


tages  in  sensitiveness.  Mr.  England's  fornmia  for  collodion 
is  as  follows : 

To  five  parts  of  ether  and  three  of  alcohol,  add  sufficient 
pyroxyline  to  give  a  tolerably  thick  film.  As  soon  as  it  has 
well  settled,  decant  the  clear  supernatant  part  into  another 
bottle,  and  measure  off  two  portions  of  ten  drachms  each ; 
to  one  add  forty  grains  of  bromide  of  cadmium,  and  to  the 
other  thirty  grains  of  iodide  of  ammonium ;  shake  till  dis- 


one  drachm  of  each  to  six  parts  of  plain  collodion. 

Sensitize  in  a  neutral  bath  of  nitrate  of  silver,  containing 
forty  grains  of  nitrate  of  silver  to  the  ounce  of  water,  and 
wash  afterward  in  a  dish  of  distilled  water,  rendered  acid  by 
acetic  acid.  The  plate  is  left  in  this  dish  until  a  second  one 
is  prepared ;  it  is  then  taken  out  and  washed  thoroughly  be- 
neath the  tap,  flowed  with  distilled  water,  and  coated  with 
the  following  solution : 

Tannin,  15  grains. 

Honey,  15  grains. 

Distilled  water,  1  ounce. 

Coat  as  before  directed,  wash  and  dry.  Protect  the  edges  of 
the  film  with  varnish. 

After  exposure,  immerse  the  plate  in  a  bath  of  nitrate  of 
silver,  ten  grains  to  the  ounce,  as  follows : 

Nitrate  of  silver,   2  drachms. 

Distilled  water,  12  ounces. 

Acetic  acid,  1  drachm. 

Keep  the  plate  in  this  bath  for  one  minute,  and  then  develop 
with  the  pyrogallic  acid  developer  as  usual,  or  according  to 
the  method  in  the  Tannin  process  just  described. 

Mr.  Anthony,  of  New-York,  finds  it  advantageous  to  fume 
the  Tannin  plates  for  a  few  seconds  with  the  vapor  of  am- 
monia, for  instance,  the  evening  before  their  exposure,  the 
time  of  which  is  said  to  be  shortened  by  this  process. 


This  is  the  simplest  of  all  dry  processes,  the  discovery  of 
Despratz.  It  consists  simply  in  dissolving  in  the  collodion 
about  two  and  a  half  grains  of  powdered  resin  for  every 
ounce  of  collodion.  After  sensitization  the  plate  is  well 
washed  and  dried.  The  development  and  all  other  manipu- 
lations are  the  same  as  in  the  wet  collodion  process.  Dubosq 
makes  use  of  amber,  and  Hardwich  of  Glycirrhizine  for  the 
same  purpose. 


When  thoroughly  settled,  add 


Resin  Process. 


250 


DR.  HILL  NORRIS'S  PROCESS. 


Sutton's  Rapid  Pry  Process. 
The  operations  in  this  process,  as  furnished  by  Sutton,  aro 
as  follows : 

1.  Clean  the  glass  plate,  dry  it  thoroughly,  and  apply  to 
it  a  solution  composed  of  one  grain  of  India-rubber,  dissolved 
in  an  ounce  of  keroselene. 

2.  Coat  the  plate  thus  prepared  with  bromo-iodized  collo- 
dion, containing  an  equal  number  of  atoms  of  iodine  and  bro- 
mine, added  in  combination  with  cadmium.  There  should 
be  about  five  grains  of  mixed  iodide  and  bromide  of  cadmium 
to  the  ounce  of  collodion. 

3.  Excite  the  film  in  a  bath  composed  of  thirty  grains  of 
pure  recrystallized  nitrate  of  silver,  slightly  acidified  with 
nitric  acid. 

4.  Wash  off  all  the  free  nitrate  of  silver,  and  pour  over  the 
film  a  preservative  composed  of  twenty-five  grains  of  gum- 
arabic  freshly  dissolved  in  an  ounce  of  water.  Let  it  dry 
spontaneously,  and,  before  putting  the  plate  into  the  dark- 
slide,  dry  it  again  thoroughly  before  a  hot  flat-iron. 

5.  Give  the  same  exposure  as  for  wet  collodion. 

6.  Develop  the  picture  by  first  wetting  it  with  distilled 
water,  and  then  pouring  over  it  a  developer,  consisting  of 
one  ounce  of  distilled  water,  two  grains  of  pyrogallic  acid, 
two  scruples  of  glacial  acetic  acid,  and  a  few  drops  of  a  weak 
solution  of  nitrate  of  silver.  The  image  appears  immediately, 
and  very  soon  acquires  the  necessary  intensity. 

7.  Fix  the  negative  in  the  usual  way,  with  a  saturated  so- 
lution of  the  hyposulphite  soda  or  lime,  and  when  dry,  var- 
nish it  with  spirit  varnish. 

Keends  Rapid  Dry  Process. 

This  is  a  modification  of  the  Tannin  Process,  or  Tannin 
and  Honey  Process.  The  characteristic  difference  is  this : 
After  the  plate  is  sensitized,  it  is  not  washed,  but  flowed  im- 
mediately with  equal  parts  of  a  filtered,  fifteen  grain  per 
ounce  solution  of  tannin  and  gum,  the  latter  consisting  of 
four  ounces  of  picked  gum-arabic,  dissolved  in  eight  ounces 
of  rain-water.  The  collodion  plate  requires  twice  the  time 
in  the  nitrate  bath  of  an  ordinary  collodion  plate.  When  re- 
moved from  the  bath,  drain  a  few  moments  and  flow  it  with 
the  preservative  mixture  bountifully,  as  with  collodion,  tilt- 
ing the  plate,  so  that  the  tannin  solution  flows  from  the  right 
upper  corner  to  the  left  upper  corner,  then  to  the  left  lower 
corner,  and  finally  to  the  right  lower  corner,  and  then  along 


DR.  HILL  NORRIS'S  PROCESS. 


251 


with  the  excess  of  water  off  at  this  corner.  Repeat  the  opera- 
tion once  or  twice.  The  last  lot  can  be  nsed  for  the  first  of 
the  next  plate.  The  plate  is  then  drained,  washed  and  dried. 
It  is  said  to  be  almost  as  sensitive  as  a  wet  collodion  plate. 
It  is  soaked  in  distilled  or  rain-water  before  it  is  developed. 
It  is  fixed  and  developed  like  any  other  tannin  plate. 


CHAPTER  XXXVIH. 


PRINTING  OF  TRANSPARENT  POSITIVES  BY  THE  DRY  PROCESS. 

Positives  on  glass,  whether  for  the  stereoscope  or  the  magic 
lantern,  that  is,  such  as  are  to  be  regarded  by  transmitted 
light,  are  prepared  most  easily,  most  quickly,  and  most  effect- 
ually by  the  Dry  Process.  The  first  part  of  the  operation 
consists  in  obtaining  a  correct  negative  of  the  object,  either 
by  the  wet  or  the  dry  process,  the  latter  being  preferable, 
because  the  negative  so  obtained  is  less  liable  to  be  damaged 
in  the  subsequent  manipulations  than  the  ordinary  unvar- 
nished collodion  negative.  The  negative  in  question  is  re- 
quired to  be  very  sharp  in  all  its  parts,  moderately  dense  in 
the  deepest  shades,  though  not  so  much  so  as  for  the  ordinary 
printing  on  paper,  and  transparent  in  the  lights.  The  film 
must  be  thin,  bright,  and  free  from  all  deposit  of  dust  arising 
from  reduction  or  impurities.  The  negative  best  adapted 
for  the  printing  of  glass  transparencies  is  incontestably  that 
with  albumen  ;  for  it  requires  no  varnish,  and  is  endowed 
with  all  the  requisites  above  mentioned.  The  albumenized 
glass,  too,  is  the  best  for  the  reception  of  the  transparent  image. 
Dry  plates  by  the  Tannin  Process  are  the  next  best ;  it  is  a 
good  plan  in  this  instance  also  to  have  the  negative  an 
albumen  print,  and  the  transparencies  on  tannin  plates. 

Provided  with  such  a  negative,  place  it  in  the  shield  of 
the  plate-holder  with  the  image  toward  you  ;  on  this  place 
a  sensitized  tannin  or  albumen  plate,  the  film  being  from  you, 
so  that  the  two  films  lie  in  intimate  juxtaposition ;  close  the 
door,  whose  spring  retains  the  plates  firmly  in  contact.  In- 
troduce the  plate-holder  into  the  grooved  receptacle  at  one 
end  of  the  cylinder,  as  described  in  a  previous  chapter  of  this 
work,  expose  the  other  end  to  the  light  of  a  cloud,  etc.,  and 
draw  the  slide.  An  exposure  of  a  few  seconds  will  be  all- 
sufficient.  The  precise  time  can  not  be  accurately  given,  but 
is  easily  ascertained  with  given  materials.  Begin  with  an 
exposure  of  one  second,  and  proceed  until  you  find  the  time 
best  adapted  for  the  circumstances.    With  dry  plates,  it  is 


PRINTING  BY  THE  DRY  PROCESS. 


253 


not  absolutely  necessary  to  use  the  cylinder ;  the  cylinder, 
nowever,  yields  superior  results. 

The  development  of  the  plate  depends  upon  the  nature  of 
its  constitution  ;  if  an  albumen  plate,  develop  it  accordingly  : 
if  a  tannin  plate,  in  like  manner.  These  different  modes  are 
given  in  detail  in  the  preceding  chapters  on  the  subjects  in 
question ;  as  well  as  every  other  information  referring  to  the 
completion  of  the  picture  after  development,  such  as  wash- 
ing, fixing,  drying,  and  varnishing. 

The  color  of  an  albumen  print  is  not  sufficiently  agreeable 
for  stereoscopic  purposes.  This  color  is  improved  by  im- 
mersing the  plate  in  the  first  place  in  a  dilute  solution  of 
bichloride  of  mercury,  and  after  it  has  been  washed,  in  a 
solution  of  sel  d'or,  (the  double  hyposulphite  of  gold  and 
of  soda,)  when  the  color  will  be  an  agreeable  sepia  tone. 

Chloride  of  gold  alone,  in  dilute  solution,  communicates  to 
the  fixed  positive  an  agreeable  purple  tone ;  naturally  the 
prints  have  to  be  washed  always  after  such  operations. 

To  take  Copies  of  any  given  size. 

Where  the  required  transparency  must  be  of  a  given  size, 
as  is  the  case  in  the  preparation  of  slides  for  the  magic  lan- 
tern, and  for  other  similar  exhibitions,  or  for  church  win- 
dows, the  printing  has  to  be  performed  in  the  camera  and 
by  means  of  the  lens.  This  process  is  described  in  a  pre- 
ceding chapter  of  this  work. 

Theoretically  a  picture  can  be  made  as  many  times  larger 
or  smaller  than  the  original  by  an  analysis  of  the  well-known 
formula  for  the  conjugate  foci  of  a  double  convex  lens.  This 
formula  is  as  follows : 

1  __  1  J_ 
v  ~  f  u 

where  the  thickness  of  the  lens  is  not  taken  into  consider- 
ation ;  but  with  this  consideration,  the  formula  will  be  : 

v      j        u      $  \     r         u  ' 

when  any  two  of  the  preceding  terms  f,  and  w,  are  known, 
the  third  can  be  found ;  f  signifies  the  principal  focal  dis- 
tance ;  u  the  distance  of  the  object  from  the  nearest  surface 
of  the  lens ;  v  is  the  distance  of  the  picture  on  the  ground 
glass  from  the  same  surface ;  t  is  the  thickness  of  the  lens ; 
r  the  radius  of  curvature  of  the  first  surface ;  and  p  is  the 
index  of  refraction  of  the  transparent  medium  of  which  the 
lens  is  formed. 


254  PRINTING  OF  TRANSPARENT  POSITIVES 


Without  going  into  a  minute  optical  discussion,  I  will 
analyze  the  first  formula  so  as  to  be  enabled  with  a  lens  of  a 
given  power,  and  with  a  given  sized  object  to  show  what 
must  be  the  respective  distances  of  the  object  and  image 
from  the  lens. 

In  the  first  place  I  will  explain  a  few  technical  terms, 
such  as  the  axis  of  a  lens,  the  optical  center  of  a  lens,  the 
principal  focus  of  a  lens,  the  conjugate  foci  of  a  lens,  the 
equivalent  focus  of  a  combination. 

The  axis  of  a  lens  is  a  line  perpendicular  to  all  the  diam- 
eters drawn  from  edge  to  edge. 

The  optical  center  of  a  lens  is  the  point  where  a  line  (join- 
ing an  impingent  and  an  emergent  ray  that  are  parallel  to 
each  other)  crosses  the  axis ;  this  center  is  sometimes  within 
the  lens,  sometimes  on  its  surface,  and  sometimes  external 
to  it. 

The  principal  focus  of  a  lens  is  the  point  where  parallel 
impingent  rays  converge  and  cross  after  refraction  and 
emergence ;  it  is  the  burning  point  of  the  sun's  rays.  The 
distance  of  this  point  to  the  optical  center  is  called  the  prin- 
cipal focal  distance. 

The  conjugate  foci  are  any  point  on  an  object  and  its  cor- 
responding point  on  the  image.  The  distances  of  these  two 
points  to  the  optic  center  are  denominated  conjugate  focal 
distances  ;  these  distances,  however,  are  generally  reckoned 
from  the  vertex  or  surface  of  the  lens  next  to  the  object. 

The  vertex  is  that  point  where  the  axis  touches  the  sur- 
face of  the  lens  nearest  the  object. 

The  equivalent  focus  is  a  term  that  refers  to  compound 
lenses,  such  as  those  used  by  the  photographer;  it  is  the 
principal  focus  or  the  focus  of  parallel  rays  of  the  combin- 
ation. It  is  called  equivalent  from  being  compared  with  a 
single  lens  that  will  produce  the  same  sized  picture  at  the 
same  distance  of  the  object.  If  rays  from  an  object  impinge 
upon  a  lens  and  on  emerging  converge,  they  wall  cross  each 
other,  and  where  they  cross  they  will  form  a  picture  of  the 
object. 

The  axis  of  a  radiant  point,  that  is,  of  any  point  on  an 
object,  does  not  mean  the  same  thing  as  the  axis  of  the  lens; 
it  is  a  line  that  is  broken  at  the  two  surfaces  of  the  lens, 
passing  through  the  optic  center,  of  which  the  impingent 
and  emergent  parts  are  parallel.  On  this  axis  the  image  of 
the  object  is  found.  If  rays  emerge  parallel,  they  will  never 
cross,  and  therefore  produce  no  picture;  if  they  diverge 


BY  THE  DRY  PROCESS. 


255 


after  emergence,  the  image  will  be  on  the  same  side  of  the 
lens  with  the  object,  and  is  denominated  a  virtual  image. 

Equidistant  conjugate  focus  refers  to  an  object  and  its 
image  on  the  ground  glass  when  they  are  equidistant  from 
the  optical  center,  or  more  intelligibly  speaking  for  the 
photographer,  when  the  image  and  the  object  are  of  the 
same  size.  The  distance  of  the  equidistant  conjugate  focus 
can  be  derived  from  the  principal  focal  distance,  or  vice 
versa.    Thus  in  the  equation  : 

J___l  1_ 

v  ~  f  ~~  u 

let  f=12  inches,  required  the  value  of  v  and  u  when  they 
are  equal,  or  when  the  picture  and  object  with  the  lens  in 
question  are  of  the  same  magnitude  ?    By  transposition 

1112        12  . 

—r=  1  —  or  -r7r==  or  a =24  inches. 

f      v       v       v        12  v 

Therefore  if  a  given  single  lens  has  a  principal  focus  of 
12  inches,  the  ground  glass  as  well  as  the  object  will  have 
to  be  placed  respectively  at  a  distance  of  24  inches  from  the 
lens  in  order  to  obtain  a  picture  of  the  same  size  as  the 
object. 

The  principal  focal  distance  of  a  single  lens  can  be  found 
with  sufficient  accuracy  for  all  practical  purposes  by  measur- 
ing the  distance  of  the  lens  from  the  burning  point,  and  by 
adding  to  this  distance  half  the  thickness  of  the  lens. 

The  principal  focal  distance  of  a  combination  can  be 
found  with  the  same  degree  of  accuracy  by  adjusting  the 
camera  before  a  given  line  so  that  the  image  of  the  line  on 
the  ground  glass  is  exactly  of  the  same  size.  One  fourth 
of  the  distance  between  the  object  and  the  image  is  the 
principal  focus  required.  For  instance,  let  this  distance  be 
48  inches,  then  v  is  24  and  u  is  24  inches ;  by  substitution 

1      1       1      2      1        *  -ft  •  . 

7"=  24 =^4  =T2'  °r /==12  mcheS' 

The  distance  of  either  the  image  or  the  object  from  the 
optical  center  bears  a  direct  ratio  with  the  size  of  the  image 
or  the  object,  whether  the  lens  be  single  or  compound. 
Thus  then,  if  we  know  the  respective  linear  magnitudes  of 
the  image  of  the  same  object  as  obtained  by  two  single 
lenses  or  by  a  single  lens  and  a  combination,  as  well  as  the 
principal  focal  length  of  the  former,  (which  can  always  be 
easily  obtained  by  the  sun's  rays,)  we  can  by  the  legitimate 


256 


PRINTING  OP  TRANSPARENT  POSITIVES 


proportion  derive  the  principal  focus  of  the  other  single 
lens  or  the  equivalent  focus  of  the  compound  lens.  For  in- 
stance, let  the  principal  focal  length  of  a  single  lens  be  3 
inches,  and  the  linear  magnitude  of  an  image  of  a  given 
object  be  2  inches  as  obtained  by  this  lens  ;  let  also  5  inches 
be  the  linear  magnitude  of  the  image  of  the  same  object  at 
the  same  distance  when  taken  by  another  lens ;  required 
the  principal  focal  length  of  the  other  lens,  (if  single,)  or 
the  equivalent  focal  length  of  the  combination  ? 

L.M.     P.F.      L.M.  INCHES. 

By  proportion  as  2  :  3  :  :  5  :  7i  the  principal  focal  length  required. 

In  the  proportion  -i-rr— -  -f  -i,  let  u  be  n  times  larger  than  % ; 
required  the  proportion  that  f  bears  to  u  t 

1       1       1     nv  +  v    n  +  1 
f  ~  v      nv  ~  ntf       nv  °Y 
nv=f  (n  +  l\  but  u=nv 
u=f(n+l)  and 
v=f(n  +  l) 
n 

Hence  if  we  multiply  the  principal  focal  length  of  any 
lens  by  one  more  than  the  times  the  image  is  linearly  greater 
than  the  object,  we  shall  obtain  the  distance  the  screen  is  to 
be  placed  from  the  lens ;  and  if  we  divide  this  latter  pro- 
duct by  the  number  of  times  the  image  is  linearly  greater 
than  the  object,  we  obtain  the  distance  of  the  object  from 
the  lens.  In  these  analytical  conclusions  we  suppose  the 
lens  to  be  single  and  very  thin.  The  deductions  thus  de- 
rived have  to  be  regarded  in  reference  to  the  center  of  the 
combination.  The  following  table  has  been  constructed  in 
accordance  with  the  preceding  principles,  and  it  exhibits 
the  distances  between  the  object  and  the  lens,  the  image 
and  the  lens,  and  the  object  and  the  image.  Any  degree  of 
reduction  and  enlargement  with  a  given  lens  or  combination, 
whose  equivalent  focus  is  known,  can  be  effectuated  with 
great  ease  by  adjusting  the  object  and  the  ground  glass  at 
the  distances  indicated. 

0  in  the  following  table  stands  for  the  distance  between 
the  object  and  the  center  of  the  combination. 

1  stands  for  the  distance  between  the  image  and  the  center 
of  the  combination. 

S  stands  for  the  distance  between  the  object  and  tho 
image,  or  the  sum  of  the  two  preceding. 


BY  THE  DRY  PROCESS, 


257 


Application  of  the  Preceding  Table. 

If  the  equivalent  focus  or  principal  focal  length  of  a  com- 
bination be  known,  it  is  very  easy  to  arrange  the  object  to 
be  photographed,  the  camera  and  the  screen,  so  as  to  produce 
a  picture  so  many  times  larger  or  smaller  than  the  object,  as 
may  be  required ;  for  instance,  let  the  focal  length  of  the 
combination  be  4^  inches,  what  must  be  the  conditions  of 
the  three  things,  object,  combination,  and  ground  glass,  so 
as  to  obtain  an  image  eight  times  larger  than  the  object  ? 

Look  for  \\  in  the  first  vertical  column,  and  for  8  on  the 
first  horizontal  line ;  where  these  two  columns  meet  will  be 
found  all  that  is  required.  In  the  first  place  the  object  and 
the  ground  glass  must  be  45T9g  inches  apart,  the  ground  glass 
is  40^-  inches  from  the  middle  of  the  combination,  and  the 
object  is  consequently  5-^  inches  from  the  same  point. 

If  we  wish  to  diminish  the  size  of  the  picture  eight  times, 
then  the  two  latter  of  the  above  terms  are  inverted,  the  ob- 
ject being  45-^  from  the  center  of  the  combination,  and  the 
image  only  5T^  inches  from  the  same  point. 

The  table  can  be  extended  as  far  as  desired,  by  using  the 
multiples  of  the  numbers  already  given.  If  we  required  the 
conditions  for  15  inches  focus,  multiply  those  along  column 
5  by  3,  the  results  will  be  the  conditions  required. 

Microphotograpliy  and  Macropliotography. 
This  branch  comprehends  the  mode  of  taking  photographs 
♦of  microscopic  or  almost  invisible  objects,  as  also  of  amplifi- 
cation by  means  of  the  solar  camera.  In  either  case  means 
are  resorted  to  by  which  light  can  be  concentrated  or  con- 
densed on  the  object  or  collodion  positive  to  be  copied,  and 
enlarged  or  diminished.  These  means  are  combinations  of 
plane  reflectors,  concave  reflectors,  double  convex  or  plano- 
convex lenses.  The  appendages  to  the  solar  camera  and 
to  the  solar  microscope  are  flic-similes  of  each  other  ;  but 
the  solar  microscope  existed  before  photography  had  been 
elicited  from  chaos  ;  the  solar  camera,  therefore,  is  a  mere 
imitation  of  its  antecedent ;  the  patentees  of  the  latter  instru- 
ment, then,  can  make  no  claim  to  originality  of  design  ;  their 
only  claim  can  be  the  application  of  the  instrument  to  pho- 
tography. 

Solar  Microscope. 
The  appendages  to  the  solar  microscope,  that  is,  the  con- 
densing part  of  the  apparatus,  consist  in  the  first  place  of  a 
plane  mirror  in  the  form  of  a  rectangle,  whose  width  is  at 
least  equal  to  the  diameter  of  the  plano-convex  or  double 


258  PRINTING  OF  TRANSPARENT  POSITIVES 

convex  lens,  which  condenses  the  light  received  from  the 
mirror.  The  length  of  the  mirror  must  be  about  four  times 
its  width.  At  one  end  there  is  a  hinge-joint,  which  allows 
the  mirror  to  swing  on  the  same  like  a  door.  The  hinge  is 
fixed  to  a  circle  of  brass  or  other  metal,  which,  by  means  of 
a  dentated  periphery,  admits  of  a  circular  motion.  By  this 
contrivance  it  will  be  seen  that  the  mirror  has  two  motions 
at  right  angles  to  each  other ;  for  instance,  supposing  the 
back  of  the  mirror  faced  the  sun  at  noon,  and  were  perpen- 
dicular to  the  horizon,  then  one  of  the  motions  mentioned 
would  cause  the  mirror  to  incline  toward  the  sun,  until  finaMy 
it  would  be  flat  on  the  horizon.  The  other  motion  permits 
the  mirror  to  move  either  toward  the  East  or  the  West ;  so 
that,  as  it  now  stands,  if  moved  toward  the  West,  the  sil- 
vered surface  would  face  the  setting  sun.  By  combining 
these  two  motions  consentaneously,  the  mirror  can  always  be 
so  inclined  as  to  reflect  the  rays  of  the  sun  from  rising  to 
setting  into  the  axis  of  the  condenser.  The  two  motions  in 
question  are  effected  by  means  of  screws  and  pinion- wheels, 
etcetera. 

The  part  just  described  might  be  a  concave  mirror  admit- 
ting of  the  same  motions  ;  this  would  act  as  a  reflector  and 
condenser  at  the  same  time.  The  condenser  is  fixed  in  the 
brass  plate  which  is  attached  to  the  window-shutter,  and 
around  the  condenser  the  metallic  ring  moves,  to  which  the 
hinge  of  the  mirror  is  attached.  The  object  of  this  part  of 
the  apparatus  is,  by  refraction,  to  cause  the  large  bundle  of 
parallel  rays  that  impinge  upon  its  surface,  to  be  condensed 
from  a  cylindrical  into  a  conical  form,  so  that  at  a  given  dis- 
tance this  converging  and  condensed  light  will  arrive  at  its 
apex  or  focus. 

Now,  at  this  focus,  all  the  light  that  has  passed  through  the 
lens  will  be  concentrated  ;  and  at  a  variable  distance,  before 
it  arrives  at  this  focus,  it  will  cover  a  variable  space,  vary- 
ing from  a  point  or  zero  upward  to  an  amount  equal  to  the 
surface  of  the  lens. 

The  amount  of  condensation  will  be  the  ratio  between  the 
squares  of  the  distances  from  the  focal  point ;  thus,  supj>ose 
the  focal  distance  be  twelve  inches,  and  that  we  intercept 
the  cone  of  light  at  three  inches  from  the  focus ;  then  by  di- 
viding the  square  of  twelve  by  the  square  of  three  we  obtain 
the  ratio,  which  is  sixteen,  and  this  indicates  that  the  light 
at  this  distance  is  sixteen  times  more  intense  than  it  was 
when  it  first  immerged  from  the  lens. 

The  object  of  the  refracting  lens,  therefore,  is  to  illumine 


BY  THE   DRY  PROCESS. 


259 


the  object  with  light.  This  is  the  primary  view  of  the  matter, 
but  it  does  more  than  this ;  each  ray  from  the  condenser  not 
only  illumines  each  point  on  the  transparent  object  upon 
which  it  impinges,  but  on  emergence  after  refraction  it  passes 
on  modified  by  the  medium  through  which  it  has  penetrated, 
and  carries,  so  to  say,  this  part  of  the  picture  with  it ;  the 
cone  of  modified  light  is  in  fact  the  picture  set  in  motion,  and 
so  directed  as  to  strike  the  surface  of  the  camera-lens  which 
is  next  to  it.  These  rays  are  convergent,  and  are  each  the 
axis  of  an  independent  cone  of  divergent  rays  from  each  illu- 
mined point  of  the  transparent  negative.  Some  photogra- 
phers maintain  that  the  axes  alone  (that  is,  the  rays  that  con- 
stitute the  cone  of  light  from  the  condenser)  are  available, 
and  that  the  divergent  rays  around  each  axis  are  of  no  avail. 
This,  however,  is  a  mistake,  and  is  equivalent  to  saying  that, 
if  an  opaque  object  were  illumined  by  a  condenser  or  reflec- 
tor, the  picture  could  be  taken  only  by  focussing  the  cone  or 
the  beam  of  reflected  light ;  whereas  we  know  full  w^ell  in 
copying  that  the  rays  that  enter  the  camera  through  the  lens, 
and  that  go  to  the  formation  of  the  picture,  can  not  be  any 
of  the  reflected  rays,  because  these  are  perpendicular  to  the 
surface  of  the  copy,  and  would  indicate  that  the  impingent 
rays  were  also  perpendicular,  which  is  an  impossibility,  ow- 
ing to  the  opacity  of  the  camera  and  its  tube,  which  occlude 
all  perpendicular  rays.  On  the  contrary,  each  illumined  point 
becomes  a  new  radiant,  from  which  proceeds  a  divergent  pen- 
cil of  rays,  of  which  many  around  the  axis  are  refracted  by 
the  lens  and  brought  to  a  focus  on  the  other  side. 

If  the  condensing  lens  be  achromatic,  the  light  will  be 
white  ;  if  not  achromatic,  it  will  produce  spectral  colors,  of 
which  some  are  useless  in  photography,  whilst  others  are 
exactly  those  which  are  needed.  Now  the  scientific  optician 
can  arrange  his  non-achromatic  condenser  in  .such  a  manner, 
in  reference  to  the  lens  and  the  negative,  as  to  make  use  only 
of  the  violet  light,  or  the  actinic  part  of  the  spectrum,  for 
the  formation  of  the  picture.  The  focus  of  the  violet  or  ac- 
tinic light  is  shorter  than  that  of  the  luminous  or  yellow  part. 

The  next  appendage  to  the  solar  microscope  is  the  object" 
holder,  which  has  a  sliding  motion  to  or  from  the  condenser, 
in  the  neighborhood  of  the  focus,  by  which  means  the  object 
can  be  placed  in  a  condensed  part  of  the  cone  of  light,  which 
is  just  sufficient  to  cover  it  and  no  more,  a  contrivance  by 
which  light  is  economized. 

The  remaining  part  of  the  instrument  is  the  microscope 
I'd 


260 


PRINTING  OF  TRANSPARENT  POSITIVES 


proper,  which  contains  the  corrected  objective  for  magnify- 
ing the  object. 

Now  the  above  description  is  precisely  the  same  as  that 
of  the  condensing  part  of  the  solar  camera.  With  such  an 
arrangement  of  mirrors  and  refractors,  the  camera  and  screen 
may  remain  fixed  during  the  whole  time  of  the  operation. 

Another  arrangement  for  concentrating  light  is  accom- 
plished by  means  of  reflectors  fixed  in  the  form  of  a  frustum 
of  a  pyramid.  But  in  the  application  of  this  contrivance 
the  camera  and  screens  must  all  move  together  on  a  univer- 
sal joint,  like  a  heliostat,  by  which  means  the  silvered  sur- 
faces of  the  reflectors  can  always  be  preserved  in  front  of 
the  sun,  so  as  to  catch  his  rays,  (as  described  in  a  pre- 
vious chapter  of  this  work.) 

The  mode  of  using  the  solar  microscope  and  the  solar  cam- 
era is  in  no  wise  different,  excepting  that  in  the  former  a 
transparent  object  is  substituted  in  the  holder  for  the  trans- 
parent collodion  negative  in  the  latter.  Each  is  placed  in 
the  cone  of  condensed  light,  in  order  to  be  brilliantly  illu- 
mined, and  in  such  a  position,  in  reference  to  the  objective 
or  photographic  lens,  as  to  bring  the  focus  of  the  actinic  rays 
immediately  on  the  optical  center  of  the  last  or  front  lens  of 
the  combination.  It  is  by  this  means  alone  that  the  best  en- 
larged picture  can  be  obtained. 

How  to  find  the  point  where  the  Lens  is  to  be  placed. 

It  appears  then  that  the  lens  may  not  be  placed  in  any  po- 
sition for  maximum  effect ;  the  true  position  depends  upon  the 
power  of  the  condenser,  in  combination  with  the  power  of 
the  posterior  lens  of  the  tube,  where  such  is  used.  There 
must  be  a  relative  connection  between  these  two  powers ; 
but  this  is  not  maintained  in  any  of  the  solar  cameras  in  the 
market,  from  the  fact  that  tubes  are  not  considered  as  parts  of 
the  solar  camera ;  operators  are  consequently  left  to  apply 
whatever  combination  they  may  have  on  hand ;  we  must 
therefore  avail  ourselves  of  what  is  next  best,  and  fix  the 
combination  where  the  maximum  effect  can  be  obtained  witli 
given  materials. 

Knowing  the  length  of  the  principal  focus  of  the  conden- 
ser and  its  diameter,  as  well  as  that  of  the  compound  lens 
from  the  posterior  lens,  the  mathematician  can  easily  calcu- 
late how  much  the  former  focus  will  be  shortened  by  the  in- 
terposition of  the  tube.  Supposing,  for  instance,  the  diame- 
ter of  the  condenser  be  eight  inches,  and  its  focal  length  be 
twelve  inches,  then  the  angle  which  the  side  of  the  cone  of 


BY  THE  DRY  PROCESS. 


2G1 


condensed  light  makes  with  the  diameter  will  be  71°  '.23 
Moreover,  let  the  diameter  of  the  posterior  lens  be  two 
inches,  and  the  focal  length  from  the  back  lens  two  inches, 
then  the  angle  formed  between  the  side  of  its  cone  and 
the  diameter  will  be  63°  45'.  That  is,  if  the  rays  entered 
the  combination  parallel,  they  would  form  a  cone,  of  which 
the  outside  ray  would  have  this  angle  with  the  diameter  of 
the  back  lens.  But,  being  interposed  in  the  cone  of  condens- 
ed light,  of  which  the  rays  are  convergent,  the  tendency  of 
the  combination  is  to  shorten  the  focal  length,  by  reducing 
the  angle  63°  45'  to  56°  00',  the  difference  between  these 
two  angles  being  the  same  difference  that  exists  between  71° 
32'  and  63°  45'.  As  the  angle  diminishes,  so  will  the  focal 
length  of  the  cone  of  condensed  light  be  diminished,  and  in 
the  present  instance  to  the  amount  of  half  an  inch. 

Besides  this,  we  have  to  reduce  this  distance  still  more,  in 
order  to  find  the  actinic  focus,  which  the  mathematical  opti- 
cian can  easily  find. 

But  the  generality  of  photographers  are  not  supposed  to 
be  in  a  condition  to  deduce  the  requisite  corrections  in  this 
way ;  we  must  therefore  show  by  practical  means  how  we 
can  approximate  to  the  same  results. 

Ascertain  the  focal  length  of  the  condenser  by  finding  the 
distance  of  its  burning  point  from  the  glass ;  then,  when  the 
tube  is  screwed  out  to  the  extent  of  its  play,  measure  the 
distance  from  the  face-plate,  in  which  the  tube  is  fastened, 
to  the  front  lens  ;  subtract  this  distance  from  the  focal  length 
of  the  condenser,  the  difference  will  give  the  distance  of  the 
condenser  to  the  outside  of  the  camera  nearly,  or  to  the  part 
upon  which  the  face-plate  of  the  tube  is  to  be  screwed.  More 
accurately  the  same  result  can  be  obtained  by  interposing 
the  tube  in  the  condensed  light,  and  by  moving  it  backward 
and  forward,  until  the  focal  or  burning  point  is  just  on  the 
outside  of  the  front  lens ;  let  an  assistant  measure  this  dis- 
tance from  the  outside  of  the  camera,  and  at  this  distance 
fix  the  tube  permanently.  Whilst  doing  this  the  greatest 
care  is  required  to  make  the  axis  t)f  the  condenser  coincide 
with  the  axis  of  the  tube. 

This  is  the  first  rude  adjustment.  The  second  adjustment 
consists  in  bringing  the  actinic  focus  so  as  to  coincide  with 
the  optic  center  of  the  front  lens.  Screwr  back  the  sliding 
part  of  the  tube  and  turn  on  the  sun  ;  the  luminous  focus  will 
be  quite  visible  in  the  dark  space  behind  the  camera.  Now 
insert  a  piece  of  deep  violet-colored  glass  between  the  con- 
denser and  the  objective,  so  as  to  intercept  all  the  colors  of 


262 


PRINTING  OF  TRANSPARENT  POSITIVES 


the  luminous  cone,  excepting  the  violet,  and  ascertain  when? 
the  violet  cone  conies  to  a  focus  ;  screw  the  tube  out  until 
this  focus  is  just  in  front  of  the  anterior  glass  ;  then,  knowing 
the  thickness  of  the  front  lens,  advance  the  tube  until  the 
blue  focus  is  in  the  middle  of  the  front  lens,  and  let  this  be 
the  final  and  permanent  adjustment  of  the  tube  in  reference 
to  the  condenser.  Mark  thb  position  by  a  line  on  the  brass 
work,  in  order  that  the  tube  can  be  adjusted  at  a  moment's 
notice  when  required  to  be  used. 

The  negative-holder  is  movable  by  means  of  a  screw,  so 
that  it  can  be  brought  into  focus  upon  any  screen  on  the 
other  side  of  the  tube.  Whenever  this  operation  of  focus- 
sing is  to  be  performed,  insert  the  violet-colored  glass,  so  as 
to  focus  in  reference  to  actinism,  and  not  to  luminosity.  By 
this  means  the  luminous  picture  on  the  screen  (that  is,  when 
the  violet-colored  glass  is  removed)  may  not  be  quite  sharp, 
but  the  printed  picture  on  the  paper  will  be  sharp  and  beau- 
tifully defined.  The  same  mode  of  proceeding  may  be  fol- 
lowed with  the  ordinary  camera,  where  there  is  any  doubt 
of  the  correction  of  the  tube  for  actinism.  Place  in  front  of 
the  tube  a  piece  of  violet-colored  glass  every  time  you  focus. 

Macrophotography,  or  the  Art  of  Taking  Enlarged 
Photographs. 

The  Negative  for  Enlargement. 
The  size  of  the  negative  will  have  to  depend  on  the  diam- 
eter of  the  condenser ;  if  this  be  nine  inches,  a  one-sixth  plate 
will  be  large  enough,  the  object  being  to  get  the  negative  as 
near  the  apex  of  the  cone  of  concentrated  light  as  possible, 
and  in  such  a  position  as  to  be  totally  covered  by  the  cone. 

The  Quality  of  the  Negative. 
The  negative  suitable  for  the  solar  camera  must  be  very 
bright,  well  defined  and  quite  clear.  The  glass  must  be  thin, 
perfectly  flat,  or  in  the  same  plane  and  homogeneous.  The 
negative  effect  need  not,  in  fact,  must  not  be  carried  on  to 
the  same  extent  as  for  positive  printing ;  it  is  but  a  trifle  in 
advance  of  the  ambrotype ;  if  there  should  happen  to  be  the 
slightest  quantity  of  fogging,  that  is,  reduction  on  the  trans- 
parent parts,  it  will  be  necessary  either  to  take  another  ne- 
gative or  to  clear  off  the  fogginess.  This  is  effected  by  flow- 
ing the  plate  with  a  dilute  solution  of  iodine  in  iodide  of 
potassium,  until  the  picture  turns  slightly  cream-colored; 
the  plate  is  then  washed  and  flowed  with  a  solution  of  cyan- 
ide of  potassium,  which  dissolves  the  newly  formed  iodide 


THE  DRY  PROCESS.  263 

of  silver  and  thus  clarifies  the  picture.  As  soon  as  the  latter 
is  satisfactory,  as  to  brightness,  cleanness,  and  fine  definition, 
wash  and  dry  the  plate,  but  apply  no  varnish. 

As  soon  as  the  negative  is  in  its  place,  and  accurately  fo- 
cussed  actinically,  fix  the  prepared  paper  on  the  screen  in  its 
place.  In  order  to  preserve  the  paper  perfectly  flat  and 
smooth,  sponge  the  back  with  a  wet  sponge,  and  after  it  has 
thoroughly  expanded,  and  lies  uniformly,  and  without  undu- 
lations, go  round  the  edge  to  the  amount  of  half  an  inch  on 
the  same  surface  which  has  been  sponged  with  a  thick  solu- 
tion of  gum-arabic  ;  attach  the  paper  so  prepared  to  an  even 
plate  of  glass  or  drawing-board,  of  somewhat  smaller  dimen- 
sions than  the  paper,  and  allow  it  to  dry.  When  dry,  all 
the  corrugations  and  undulations  will  have  disappeared  ;  the 
paper  will  be  smooth  and  flat,  and  ready  to  receive  the  image, 
supposing  naturally  it  has  already  been  sensitized  in  the  sil- 
ver bath.  If  this  operation  has  been  neglected  or  omitted, 
the  silver  solution  can  be  very  expeditiously  poured  upon 
the  surface  and  spread  with  a  pad  or  tuft  of  cotton  wool, 
until  the  film  is  uniform.  The  excess  of  silver  is  then  re- 
moved, and  the  plate  is  reared  on  one  corner  over  a  wine- 
glass to  receive  the  drippings. 

When  dry  it  is  placed  in  the  focus  of  the  negative,  and 
the  sun  is  turned  on.  By  means  of  the  two  screws  on  the 
solar  camera,  the  sun's  light  is  maintained  in  its  position 
during  the  whole  operation.  Printing  on  albumenized  pa- 
per by  the  solar  camera  is  a  tedious  operation,  requiring 
sometimes  several  hours  before  it  is  complete,  and  some- 
times even  a  day  or  two  by  reason  of  the  cloudiness  of  the 
sky.  Where  this  sort  of  printing  is  practicable,  as  is  the  case 
generally  in  our  own  country,  the  results  are  the  best. 
Printing  by  development,  however,  is  more  reliable,  because 
it  is  altogether  independent  of  the  condition  of  the  sky,  wheth- 
er cloudy  or  cloudless. 

Several  processes  for  printing  by  development  will  be 
found  in  the  chapter  in  which  this  subject  has  been  discuss- 
ed. I  will  insert  another  in  this  place,  from  its  applicability 
and  reliability.  It  is  the  process  of  Blanquart-Evrard, 
whose  prints  have  been  so  much  admired. 

JBromo-iodizing  Bath  for  Paper. 


Water,   12  ounces. 

Gelatine,   1  drachm. 

Iodide  of  potassium,   1  drachm. 

Bromide  of  potassium,    15  grains. 


264 


PRINTING  OF  TRANSPARENT  POSITIVES 


Immerse  the  papers  in  this  bath,  as  many  at  a  time  as  it 
will  contain,  and  keep  them  there  for  two  or  three  hours. 
The  bath  can  be  used  over  and  over  again  until  exhausted. 
The  papers  are  then  taken  out  and  hung  up  to  dry.  As 
soon  as  they  are  dry  they  may  be  preserved  in  a  portfolio 
for  use. 

Previous  to  being  sensitized  they  are  exposed  for  a  quar- 
ter of  an  hour  to  the  vapor  of  hydrochloric  acid.  This  op- 
eration is  easily  effected  by  fixing  the  paper  along  the  sides 
and  under  the  lid  of  a  large  nearly  air-tight  box,  by  means 
of  varnished  pins.  At  the  bottom  of  the  box  place  a  saucer 
containing  a  handful  of  salt,  an  ounce  or  two  of  sulphuric 
acid,  and  half  as  much  boiling  water.  Vapors  of  hydrochlor- 
ic acid  will  be  generated  in  abundance,  and  will  thus  saturate 
the  paper. 

Sensitizing  Bath, 

Nitrate  of  silver,  1  ounce. 

Distilled  water,  14  ounces. 

Nitric  acid  to  give  it  an  acid  reaction. 

Let  the  paper  float  in  this  bath  for  ten  minutes.  By  de- 
composition they  will  now  contain  the  iodide,  bromide,  and 
chloride  of  silver.  After  sensitization  they  are  allowed  to 
drain,  and  then  dried  either  by  pressure  between  folds  of 
bibulous  paper  or  by  suspension  in  the  dark-room. 

The  exposure  required  will  vary  from  a  couple  of  seconds 
to  half  a  minute  beneath  a  negative,  and  longer  than  this  on 
the  screen  of  the  solar  camera.  When  the  image  is  just 
visible,  the  printing  has  been  carried  on  long  enough. 

Development. 

The  picture  is  brought  out  by  immersing  it  in  the  ordina- 
ry gallic  acid  bath,  at  a  temperature  of  80  degrees,  and  by 
keeping  it  there  for  a  quarter  of  an  hour  or  more  as  cir- 
cumstances require.  The  bath  must  be  large  enough  for 
many  pictures  at  a  time ;  these  are  kept  in  motion  all  the 
while.  They  assume  a  disagreeable  color,  and  become  cov- 
ered with  spots  which  are  removed  by  the  operations  after- 
ward. As  soon  as  the  depth  of  shade  is  sufficiently  intense, 
the  prints  are  taken  out,  laid  one  by  one  on  a  glass  plate,  and 
sponged  on  both  sides  and  then  immersed  in  a  bath  of  hypo- 
sulphite of  soda  for  five  minutes,  in  which  they  are  toned. 

Hyposulphite  of  soda,  1  ounce. 

Rain-water,  20  ounces. 

After  this  they  are  removed  direct  into  a  second  bath  of 
hyposulphite  of  soda  of  the  same  strength,  and  are  allowed 


BY  THE  DRY  PROCESS. 


265 


to  remain  for  twenty  minutes,  in  which  they  are  completely 
fixed. 

The  prints  are  then  carefully  washed  in  several  waters 
and  finally  immersed  in  a  bath  of  dilute  hydrochloric  acid, 
which  removes  a  yellow  deposit  and  the  spots  above  men- 
tioned. A  second  washing  completes  the  operation,  with 
the  exception  of  drying  and  exposing  to  the  action  of  light 
for  several  weeks,  which  improves  the  reddish  tone  by  chang- 
ing it  gradually  into  purple. 

These  prints  will  keep  for  an  indefinite  time,  although 
toned  with  sulphur. 

Microphotography ,  or  the  Art  of  taking  Diminished  Copies 
of  Photographs,  or  Photographs  of  Microscopic  Objects. 

Diminished  Photographs. — It  is  a  much  easier  operation 
to  diminish  the  size  of  a  photograph  or  object  by  photo- 
graphic means  than  to  amplify  one  ;  and  the  result  in  general 
is  more  satisfactory,  because  all  the  errors  of  the  original 
are  diminished  in  the  same  ratio  as  the  whole  picture  is 
diminished.  In  order  to  take  portraits  so  invisibly  small 
as  not  to  be  seen  without  the  aid  of  a  magnifier,  we  require 
a  small  camera  specially  arranged  for  the  purpose.  Such 
cameras,  furnished  with  the  necessary  objective,  are  manu- 
factured by  Bertsch  in  Paris.  The  tube  requires  no  focus- 
sing ;  the  only  condition  to  be  observed  is  to  place  the  pho- 
tograph, object,  or  print  to  be  copied  at  or  beyond  a  given 
distance.  All  lenses  have  this  property  of  requiring  but  one 
adjustment,  which  is  permanent  when  once  found,  for  objects 
beyond  a  given  distance,  which  varies  directly  as  the  focal 
distance  or  power  of  the  lens.  Lenses  for  the  diminutive 
pictures  in  question  are  in  focus  for  all  distances  beyond 
three  feet  or  so.  Objectives,  such  as  are  sold  for  microscopic 
purposes,  whose  focal  distances  are  one  inch,  half  an  inch,  or 
a  quarter  of  an  inch,  may  easily  be  arranged  in  a  very  small 
camera  to  take  these  diminutive  portraits.  But  very  little 
ingenuity  will  suffice  to  make  such  a  camera  out  of  a  small 
telescope,  where  one  tube  slides  into  another.  In  the  end 
of  the  inner  tube  the  objective  is  fixed ;  in  the  end  of  the 
outer,  the  ground  glass  and  the  plate-holder.  This  com- 
pound tube  is  fixed  permanently  upon  a  solid  support  six 
inches  high,  on  a  piece  of  board  four  or  five  feet  in  length 
or  even  more.  On  the  opposite  end  of  the  board  a  plane  is 
erected  at  right  angles  to  the  former  and  also  to  the  axis  of 
the  camera.  Find  the  point  on  this  vertical  board  where 
the  axis  cuts  the  same,  and  mark  it  as  the  center  of  the  pic- 


266  PRINTING  OP  TRANSPARENT  POSITIVES 


ture  to  be  copied.  The  picture  is  fixed  upon  this  plane  by 
means  of  tacks  or  pins  in  an  inverted  position  and  so  that 
its  center  coincides  as  near  as  possible  with  the  mark  just 
made. 

The  next  proceeding  is  to  focus  the  lens.  Take  the  long 
board  and  place  it  so  as  to  receive  the  sun's  rays  upon  the 
picture.  Now  move  the  inner  tube  of  the  camera  in  and 
out  until  the  image  is  seen  on  the  ground  glass  by  means  of 
a  powerful  magnifier.  Focus  with  the  greatest  sharpness. 
This  operation  is  very  refined  and  requires  a  great  deal  of 
patience.  When  the  utmost  definition  is  thus  obtained, 
place  before  the  opening  of  the  tube  a  piece  of  very  thin 
violet-colored  glass  and  see  if  the  image  is  still  sharp  ;  if  it 
be,  fix  the  two  tubes  permanently  so  that  their  relative  posi- 
tion can  not  be  changed.  In  future  this  operation  of  focus- 
sing is  no  longer  required.  If,  however,  the  picture  is  not 
sharp  when  the  violet-colored  glass  is  interposed,  focus  until 
you  get  perfect  definition,  and  then  fix  as  just  directed. 

The  glass  to  receive  the  picture  is  thin  and  homogeneous; 
it  is  flowed  also  with  a  very  thin  collodion  and  sensitized  as 
usual.  All  the  operations  are  precisely  the  same  as  those 
already  described  in  the  preparation  of  the  ambrotype.  Of 
course  a  pair  of  spectacles  of  very  high  magnifying  power  is 
required  while  developing,  fixing,  and  mounting.  With  a 
pair  of  pliers  or  forceps  the  small  piece  of  glass  can  be  broken 
down  so  as  to  fit  into  the  ring,  etc.,  which  is  to  receive  the 
picture. 

The  objectives  manufactured  by  Grunow  in  New-York  for 
microscropes  have  succeeded  quite  well  with  me  in  the  pro- 
duction of  almost  invisible  pictures  ;  and  I  have  no  doubt  he 
will  be  able  to  fit  up  a  microscopic  camera  for  such  as  require 
one  from  the  indications  here  given.  Such  a  camera,  requir- 
ing great  refinement  of  workmanship,  will  of  course  be  more 
likely  to  be  better  made  by  those  who  are  accustomed  to 
the  refined  adjustments  of  a  microscope  than  by  the  photo- 
grapher himself.  The  objectives  of  Grunow  are  not  only 
unexceptionable,  but  are  endowed  with  qualities  superior  to 
those  in  many  of  foreign  origin. 

Microscopic  Objects.  —  The  objectives  just  alluded  to 
are  very  well  suited  for  taking  enlarged  photographs  of 
microscopic  objects,  such  as  the  porous  structure  of  wood, 
the  siliceous  deposit  in  guano,  blood  corpuscles,  starch 
granules,  itch  insects,  etc.  Such  an  objective  is  fixed 
to  an  ordinary  bellows  camera,  so  arranged  on  a  sliding 
platform  that  the  axis  of  the  objective   coincides  with 


BY  THE  DRY  PROCESS. 


267 


the  axis  of  the  cone  of  concentrated  light  from  the 
condensBr  of  the  solar  microscope.  The  latter  instrument 
has  a  special  opening  between  the  condenser  and  the  object- 
ive to  receive  the  transparent  object  whose  photograph  is  to 
be  taken  of  an  enlarged  size.  If  the  objective  is  not  quite 
achromatic,  insert  a  piece  of  thin  violet-colored  glass  over 
the  object  while  focussing,  and  fix  the  objective  so  that  the 
violet  cone  of  light  terminates  in  the  optic  center  of  the 
objective  as  before  described.  Focus  by  means  of  a  pair  of 
very  powerful  spectacles  or  a  compound  microscope.  In  the 
first  place  make  the  camera  firm  on  the  platform,  when  the 
objective  is  once  in  its  place ;  then  draw  out  the  ground  glass 
nearly  as  far  as  it  will  go,  and  afterward  move  the  micro- 
scopic object  nearer  or  farther  off,  as  the  case  may  be,  by 
means  of  the  thumb-screw,  until  the  picture  is  visible  on  the 
ground  glass  ;  finally  focus  with  accuracy  so  as  to  get  perfect 
sharpness.  The  violet-colored  glass  may  now  be  withdrawn. 
The  prepared  collodion  plate  is  inserted  in  the  place  of  the 
ground  glass  ;  the  slide  is  drawn  out,  and  the  sun's  light 
turned  on  for  a  fraction  of  a  second.  It  is  in  many  instan- 
ces an  advantage  to  keep  the  violet-colored  glass  in  its  place, 
because  it  moderates  the  light ;  and  the  result  is  even  better 
with  it  than  without  it. 

Finish  the  plate  for  a  positive  or  negative  according  to 
rules  already  prescribed  in  ordinary  photography. 


CHAPTER  XXXIX. 


THE  DAGUERREOTYPE. 

A  photograph  on  a  silver  or  silvered  plate  is  superior  in 
definition  and  beauty  to  all  other  photographs  taken  on  other 
materials.  It  has,  however,  its  disadvantages  ;  amongst 
these  may  be  reckoned  the  lateral  inversion  of  the  picture, 
the  inability  of  regarding  the  image  at  all  angles  of  reflec- 
tion, and  of  producing  reproductions  of  the  original  by 
some  quick  printing  process. 

The  Daguerreotype  process  is  divided  into  six  different 
operations. 

First  Operation,  or  the  Cleaning  and  Polishing  of  the 
Silvered  Plates, 

Copper  plates  can  be  purchased  already  silvered  with  a 
pure  frosted  silver  surface,  of  the  proper  size  and  ready  for 
the  polishing.  In  the  first  place,  with  a  pair  of  shears,  clip 
off  the  four  corners  of  the  plate,  about  a  quarter  of  an  inch 
from  the  apex  of  each  angle  ;  next  with  the  machine  for  this 
purpose  make  a  ledge  all  round  the  plate  of  one  tenth  of  an 
inch  in  width  from  the  silver  side  toward  the  copper  side, 
so  as  to  form  a  groove  such  as  the  tinman  makes  when 
grooving  two  edges  of  tin  together.  The  plate  is  then  fixed 
on  a  patent  plate-holder,  which  in  its  turn  is  next  screwed 
tight  in  the  plate-vice.  In  this  condition  the  silvered  surface 
can  easily  be  cleaned.  This  is  effected  by  means  of  rotten 
stone,  alcohol  and  Canton  flannel,  which  are  used  in  the  same 
manner  exactly  as  in  the  cleaning  of  glass  plates.  As  soon 
as  the  plate  is  perfectly  smooth  and  free  from  scratches,  it  is 
polished  with  what  is  called  the  buff,  which  consists  of  a 
piece  of  wood,  about  fifteen  or  eighteen  inches  long,  four 
or  five  wide,  and  about  three  quarters  of  an  inch  thick ; 
this  piece  is  slightly  curved  longitudinally  like  the  rocker 
of  a  chair,  though  to  a  less  extent.  It  is  well  padded 
on  the  convex  surface  and  finally  covered  with  chamois 
leather.    On  the  surface  scatter  a  small  quantity  of  jewel 


THE  DAGUERREOTYPE. 


269 


er's  rouge,  (sesquioxide  of  iron,)  and  then  holding  the  buff 
by  either  end  in  the  right  and  left  hand  move  it  backward 
and  forward  over  the  smooth  silver  plate,  first  in  one  direc- 
tion and  then  at  right  angles  to  it,  until  the  surface  has  a 
very  uniform  rich  polish,  devoid  of  lines.  The  plate  is  then 
ready  for  being  sensitized.  The  buffing  is  more  easily  and  uni- 
formly executed  on  what  is  denominated  the  buffing- wheel. 

Second  Operation,  or  the  Sensitizing  of  the  Silver  Plate. 

For  this  purpose  two  coating-boxes  are  required,  one  con- 
taining the  vapor  of  iodine,  and  the  other  that  of  bromine. 
They  are  so  arranged  as  to  allow  the  introduction  of  the 
polished  plate  without  any  loss  of  vapor.  These  boxes  must 
be  kept  at  a  warm  temperature  so  as  to  evolve  the  vapors 
from  the  materials ;  in  winter  artificial  heat  is  used.  One 
coating-box  contains  at  the  bottom  first  a  piece  of  Canton 
flannel,  and  then  about  half  an  ounce  or  more  of  iodine  in 
crystals ;  the  other  contains  a  mixture  of  hydrated  lime  and 
bromine,  well  pulverized  and  mixed.  The  operation  is  per- 
formed in  the  dark-room  near  the  orange-colored  pane  of 
glass.  The  polished  plate  is  first  inserted  in  the  holder  of 
the  iodine  coating-box,  and  the  lid  is  then  closed.  The  sur- 
face, if  examined  closely,  assumes  various  shades  of  color, 
beginning  with  light  yellow,  then  deep  yellow,  reddish,  cop- 
per-red, violet,  blue,  and  green.  As  soon  as  the  plate  passes 
from  the  yellow  to  the  red,  it  is  placed  over  the  bromine 
vapor,  and  kept  there  until  the  reddish  color  changes  into  a 
violet  or  steel  color ;  it  is  then  put  back  again  over  the  iodine 
for  one  third  of  the  time  of  the  first  exposure.  By  this  means 
the  film  receives  a  very  high  degree  of  sensibility.  The  times 
of  these  three  exposures,  as  soon  as  determined  by  practice, 
are  counted  in  seconds.  A  more  sensitive  film  may  be  ob- 
tained by  iodizing  simply  to  the  light  yellow,  by  bromizing 
to  the  dark  yellow,  and  then  again  over  the  iodine  for  one 
third  of  the  first  exposure.  This  film,  however,  is  very  thin 
and  not  suitable  for  portraits,  although  well  adapted  for  views. 
The  plate  is  now  ready  for  the 

Third  Operation,  or  the  Exposure  to  Light. 

It  has  been  observed  that  the  sensitized  plates  are  more 
sensitive  to  the  actinic  impression  if  not  exposed  for  a  quar- 
ter of  an  hour  after  sensitization  ;  in  general,  however,  the 
plate  is  transferred  directly  from  this  operation  to  the  plate- 
holder  of  the  camera,  and  exposed  right  away.  The  time  of 


210 


THE  DAGUERREOTYPE. 


exposure  is  very  short ;  it  is  naturally  various,  as  in  all  other 
and  similar  cases  depending  upon  the  brilliancy  of  the  light, 
the  season  of  the  year,  the  time  of  the  day,  and  other  minor 
circumstances.  A  few  seconds,  even  in  the  room,  are  mostly 
quite  sufficient.  The  exact  number  is  easily  learned  from  the 
conditions  of  the  case  ;  and  then  the  exposure  afterward  can 
be  regulated  by  counting.  The  plate  is  next  withdrawn  from 
the  plate-holder  in  the  dark-room;  it  contains  no  visible 
image ;  this  is  made  to  appear  by  proceeding  to  the 

Fourth  Operation,  or  Developing  by  the  Vapor  of  Mercury, 
A  cast-iron  box  is  prepared  for  this  purpose,  capable  of 
being  well  closed  after  the  plate  is  introduced.  It  contains 
mercury  at  the  bottom,  which  is  kept  at  the  temperature  of 
from  120°  to  150°  Fahrenheit,  by  means  of  a  lamp  with  a 
small  flame  capable  of  graduation,  and  a  thermometer  attach- 
ed to  the  box  with  the  bulb  in  the  mercury.  A  couple  of 
ounces  of  mercury  will  be  sufficient  at  once  for  ordinary 
portraiture.  In  two  or  three  minutes  the  development  will 
be  complete.  At  intervals  the  plate  maybe  examined  to  see 
the  progress  of  development ;  but  this  examination  must  be 
made  with  great  care,  for  the  film  is  easily  fogged  by  expos- 
ure to  diffused  light.  If  the  time  of  exposure  has  been  too 
long,  the  whole  image  will  be  fogged  and  indistinct ;  where- 
as if  it  has  been  too  short,  the  high  lights  alone  will  be  de- 
veloped, while  the  rest  will  undergo  no  change  whatever. 
Supposing  the  picture  to  possess  the  proper  gradation  of 
light  and  shade,  it  is  then  ready  for  the 

Fifth  Operation,  or  the  Fixing  of  the  Developed  Image, 
The  film  is  still  very  sensitive,  and  the  picture  in  a  few 
minutes  would  be  irremediably  spoiled,  unless  the  sensitive 
character  of  the  film  be  annihilated.  This  is  effected  by 
plunging  the  plate  immediately  into  the  fixing  solution, 
which  must  be  preserved  in  a  very  clean  condition  by  con- 
tinual filtration  after  each  operation.  The  fixing  solution 
consists  of : 

Hyposulphite  of  soda,   2  drachms. 

Distilled  or  rain-water,  2£  ounces. 

Agitate  the  plate  in  this  solution  for  a  few  seconds,  until 
the  iodizing  is  entirely  removed,  and  then  wash  the  plate  in 
distilled  water.  In  all  operations  of  washing  and  fixing,  use 
only  filtered  materials,  for  small  particles  of  dust  are  very 
visible  on  the  dried  plates;  use,  especially,  very  pure  water, 
because  ordinary  water  contains  salts,  which  are  left  as  a 


THE  DAGUEKREOTYPE. 


211 


deposit  on  the  plates  when  dried.  After  the  fixed  plate  is 
well  washed  proceed  to  the  final  or 

Sixth  Operation,  or  the  Toning  vmh  Gold. 
In  the  first  place  make  a  ledge  round  the  plate  in  the  oppo- 
site direction,  so  as  to  form  a  miniature  dish  with  the  picture 
at  the  bottom ;  or  cut  off  the  former  ledges  entirely,  and 
he  J  ding  the  plate  by  one  of  its  corners  with  a  pair  of  pliers, 
pour  upon  the  surface  of  the  picture,  held  horizontally,  as 
much  of  the  following  gold  solution  as  it  will  hold  without 
flowing  over  the  edges  : 

Toning  Solution. 

w    j  (  Chloride  of  gold,   .1  grain. 

*    *  i  Distilled  water,  1  ounce. 

v-     *  j  Hyposulphite  of  soda,     .....    4  grains. 

°*    '  (  Distilled  water,  1  ounce. 

Dissolve  and  pour  the  gold  solution  into  the  hyposulphite 
of  soda,  and  mix  well  together.  Next  light  a  spirit-lamp 
with  a  large  wick,  and  holding  the  pliers  and  plate  in  the 
left  hand,  play  beneath  the  plate  containing  the  toning  solu- 
tion with  the  flame  of  the  lamp  held  in  the  right  hand.  Do 
not  allow  the  flame  to  play  upon  the  same  spot ;  move  it 
about,  bubbles  will  soon  begin  to  arise,  and  the  picture  will 
soon  begin  to  assume  a  much  more  agreeable  tone.  Take 
care  to  have  an  excess  of  gold  solution  all  the  time  upon  the 
plate,  otherwise,  if  it  fails  on  a  certain  part  during  the  oper- 
ation of  gilding,  a  stain  will  be  produced  that  can  not  be 
removed  by  any  subsequent  treatment.  Use  also  a  large 
flame,  to  produce  rapid  action  ;  prolonged  action  fogs  the 
picture.  When  the  tone  of  the  picture  is  satisfactory,  im- 
merse the  plate  at  once  in  a  basin  of  water,  and  wash  well 
at  the  top  ;  afterward  pour  over  the  plate  two  or  three 
times,  distilled  water,  and  then  dry  the  plate ;  beginning  at 
the  upper  edge  with  the  application  of  the  flame  of  the 
lamp,  proceed  downward,  as  the  film  dries,  blowing  off  the 
excess  of  water  as  you  proceed,  or  absorbing  it  with  a 
sponge  from  the  pendent  edge  and  corners,  until  the  whole 
surface  is  dry. 

Daguerreotypes  may  be  touched  up  with  color  like  any 
other  photographs,  where  desired.  It  must  be  confessed, 
however,  that  a  well-toned  daguerreotype  picture  looks  best 
unadorned  with  either  color  or  tinsel. 


CHAPTER  XL. 


PRINTING   WITHOUT   THE    SALTS    OF  SILVER. 

These  processes  comprehend  several  operations  with  the 
persalts  of  iron,  chromium,  the  salts  of  uranium,  and  the  car- 
bon process.  They  are  very  interesting,  but  have  not  as  yet 
been  applied  to  any  useful  purpose.  The  carbon  process  has 
not  arrived  at  that  degree  of  perfection  which  is  expected 
in  such  operations.*  This  expression  of  its  merits  is  limited 
to  direct  printing  on  paper  by  carbon  or  other  colored  media 
in  connection  with  chrome  salts,  etc.  Photo-lithography  and 
its  congeners,  that  require  the  application  of  carbonaceous 
ink,  arc  properly  classified  as  photo-engraving,  and  will  be 
treated  as  such. 

Process  with  the  Salts  of  Iron. 

Sir  John  Herschel  discovered,  several  years  ago,  that  cer- 
tain of  the  persalts  of  iron,  when  exposed  to  light  in  connec- 
tion with  organic  matter,  undergo  decomposition,  and  are 
reduced  to  the  state  of  proto-salts  ;  and  we  are  indebted  to 
Poitevin  for  numerous  interesting  developments  in  this  de- 
partment. For  instance,  the  perchloride,  so  exposed,  becomes 
reduced  to  the  proto-chloride,  or,  as  Van  Monckhoven  more 
appropriately  remarks,  to  the  state  of  oxy-chloride.  For 
this  purpose  the  sesquichloride  must  be  quite  neutral.  The 
ammonio-tartrate,  potassa-tartrate,  and  the  ammonio-citrate 
of  iron  are  much  more  sensitive  to  light  than  the  sesqui- 
chloride, and  the  latter  salt  the  most  of  all. 

The  image  formed  by  means  of  these  salts  is  much  fainter 
than  that  with  the  chloride  of  silver;  but  it  can  be  inten- 
sified by  the  application  of  other  metallic  salts.  The  mode 
of  operation  consists  in  floating  the  paper  on  the  solutions  in 
question,  in  the  dark-room,  in  allowing  them  to  dry  and  then 
exposing  them  afterward  beneath  a  negative,  as  usual,  with 
paper  prepared  with  chloride  of  silver. 

*  Pouncy's  New  Carbon  Process  seems  to  give  great  promise  of  being 
usefully  applied. 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 


273 


Cyanotype. — Float  on  a  solution  of  the  sesquichloride  of 
iron,  dry  and  expose ;  afterward  wash  the  prints,  and  then 
immerse  them  in  a  bath  of  ferridcyanide  of  potassium.  The 
picture  will  appear  of  a  blue  color  in  all  those  places  where 
the  sun  has  acted.  Ferridcyanide  of  potassium  has  no  action 
upon  the  persalts  of  iron  ;  on  the  protosalts,  however,  it 
produces  prussian  blue. 

Crysotype. — If  the  papers  containing  the  faint  image,  pro- 
duced on  the  ammonio-citrate  of  iron,  be  floated  on  a  bath 
of  a  dilute  and  neutral  solution  of  chloride  of  gold,  the  image 
assumes  a  purple  tone,  which  becomes  gradually  darker  the 
longer  it  is  exposed  to  the  solution. 

Solutions  of  the  other  metals,  such  as  those  of  silver,  mer- 
cury, and  platinum,  also  produce  images  which  are  of  a  gray- 
ish color.  Bichromate  of  potash  yields  a  picture  by  a  similar 
decomposition. 

Process  with  the  Salts  of  Uranium. 

The  discovery. of  this  process  owes  its  origin  to  Niepce  de 
St.  Victor  and  to  Burnett.  The  nitrate  of  the  sesquioxide 
of  uranium  undergoes  in  connection  with  organic  matter, 
when  exposed  to  the  sun,  a  decomposition  analogous  to  that 
of  the  sesquichloride  of  iron. 

The  paper,  without  having  undergone  any  preceding 
preparation,  excepting  that  of  having  been  excluded  from 
the  light  for  several  days,  is  floated  on  a  bath  of  the  nitrate 
of  uranium,  as  follows  : 

Distilled  water,  10  drachms. 

Nitrate  of  uranium,  2  drachms. 

The  paper  is  left  on  the  bath  for  lour  or  five  minutes  ;  it  is 
then  removed,  hung  up  and  dried  in  the  dark-room.  So  pre- 
pared, it  can  be  kept  for  a  considerable  time. 

The  exposure  beneath  a  negative  varies  from  one  minute 
to  several  minutes  in  the  rays  of  the  sun,  and  from  a  quarter 
of  an  hour  to  an  hour  in  diffused  light.  The  image,  which 
is  thus  produced,  is  not  very  distinct,  but  comes  out  in  strong 
contrast  when  developed  by  one  of  the  following  developers : 

Nitrate  of  Silver  Developer. 

Distilled  or  rain-water,  2  drachms 

Nitrate  of  silver,  7  grains. 

Acetic  acid,  a  mere  trace. 

The  development  is  very  rapid  in  this  solution ;  in  about 
half  a  minute  it  is  complete.  As  soon  as  the  picture  appears 
in  perfect  contrast,  the  print  is  taken  out  and  fixed  by  im- 
mersion in  water,  in  which  it  is  thoroughly  washed. 


274  PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 


Chloride  of  Gold  Developer, 

Distilled  water,  2  drachms. 

Chloride  of  gold,  2-J-  grains. 

Hydrochloric  acid,     .........    \  a  drop. 

This  is  a  more  rapid  developer  than  the  preceding.  This 
print  is  fixed  in  like  manner  by  water,  in  which  it  must  be 
well  washed,  and  afterward  dried.  When  dried  by  artifi- 
cial heat  the  vigor  of  the  print  is  increased.  Prints  that 
have  been  developed  by  the  solution  of  nitrate  of  silver  may 
be  immersed  in  the  gold  bath,  which  improves  their  tone. 

The  picture  may  be  developed,  also,  by  first  immersing 
the  prints  in  a  saturated  solution  of  bichloride  of  mercury, 
and  afterward  in  one  of  nitrate  of  silver.  In  this  case,  how- 
ever, the  time  of  exposure  is  increased. 

Pictures  may  be  obtained  also  by  floating  the  papers  on  a 
mixture  of  equal  quantities  of  nitrate  of  silver  and  nitrate  of 
uranium,  in  about  six  times  their  weight  of  water.  When 
dry,  they  are  exposed  beneath  a  negative.  In  this  case  the 
image  appears  as  in  the  positive  printing  process  with  chloride 
of  silver,  being  effected  by  the  decomposition  of  the  nitrate 
of  uranium,  which,  reacting  on  the  nitrate  of  silver,  decom- 
poses this  salt,  and  reduces  the  silver.  These  prints  require 
fixing  in  the  ordinary  fixing  bath  of  hyposulphite  of  soda, 
and  then  washing  as  usual. 

Process  for  Bed  Pictures. 
Float  the  papers  for  four  minutes  in  the  preceding  bath  of 
nitrate  of  uranium,  drain  and  dry.    Next  expose  beneath  a 
negative  for  eight  or  ten  minutes,  then  wash  and  immerse  in 
the  following  bath  : 

Ferridcyanide  of  potassium,   30  grains. 

Rain-water,  3  ounces. 

In  a  few  minutes  the  picture  will  appear  of  a  red  color, 
which  is  fixed  by  a  thorough  washing  in  water. 

Process  for  Green  Pictures. 
Immerse  the  red  picture,  before  it  is  dry,  in  the  following 
solution : 

Sesquichloride  of  iron,  30  grains. 

Distilled  water,  3  ounces. 

The  tone  will  soon  change  to  a  green.  Fix  in  water,  and 
dry  before  the  fire. 

Process  for  Violet  Pictures. 

Float  the  papers  in  the  following  bath  for  three  or  fowi 
minutes : 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER.  275 


Water,  .... 
Nitrate  of  uranium, 
Chloride  of  gold, 


2  ounces. 
2  drachms. 
2  grains. 


Afterward  take  them  out  and  dry.  An  exposure  of  ten  or 
fifteen  minutes  will  produce  the  necessary  reduction.  The 
picture  has  a  beautiful  violet  color,  consisting  of  metallic 
gold.    Wash  and  dry,  as  usual. 

Process  for  Blue  Pictures. 

Float  the  papers  for  a  minute  on  the  following  solution : 

Distilled  water,  5  ounces. 

Ferridcyanide  of  potassium,  1  ounce. 

Dry  in  the  dark-room,  and  then  expose  beneath  a  nega- 
tive until  the  dark  shades  have  assumed  a  deep  blue  color ; 
then  immerse  the  print  in  a  solution  of : 

Rain-water,  2  ounces. 

Bichloride  of  mercury,  1  grain. 

Wash  the  print,  and  then  immerse  it  in  a  hot  solution  of : 


This  process  aims  to  produce  a  picture  on  paper  either 
with  lampblack  or  some  other  fine,  impalpable  powder.  I 
shall  discuss  this  subject  as  distinct  from  photo-engraving  or 
photo-lithographic  operations,  although  the  two  processes 
are  based  upon  the  same  principle,  that  of  the  decomposi- 
tion of  the  bichromates  or  the  persalts  of  iron  when  exposed 
in  connection  with  organic  matter  to  the  rays  of  the  sun. 
The  chloride  of  chromium  and  the  other  salts  of  chrome,  as 
well  as  the  sesqui-salts  of  iron,  are  subject  to  this  mode  of 
decomposition.  The  rationale  of  the  operation  appears  to  be 
this :  the  chromic  acid  of  the  chromate,  or  the  sesquioxide 
in  the  case  of  iron  is  reduced  by  light  into  the  sesquioxide 
of  chromium,  or  a  protosalt  of  iron,  and  thus  parts  with 
oxygen  which  is  communicated  to  the  organic  substance  with 
which  the  salts  were  mixed,  such  as  gelatine,  gum-arabic, 
etc.,  which  in  their  turn  become  changed  in  properties  as  to 
solubility  or  insolubility,  etc. 

Various  authors  have  experimented  in  this  direction ; 
Mungo  Ponton  first  indicated  the  principle.  We  are  indebt- 
ed for  the  most  interesting  results  in  carbon  printing  to 
Poitevin,  Gamier  and  Salmon,  Pouncy  and  Fargier.  In  the 
first  experiments  of  Poitevin,  a  chromate  was  employed  in 


Water,  .... 
Oxalic  acid,  .    .  . 

Again  wash  and  dry. 


Carbon  Process. 


4  ounces. 
4  drachms. 


2  76  PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 

connection  with  gum,  gelatine  or  albumen.  His  mode  of 
operation,  as  described  in  the  Traite  de  V Impression  Photo* 
graphique  sans  sels    Argent  is  as  follows  : 

"  I  apply  different  colors  either  liquid  or  solid  to  the  pa- 
per, fabric,  glass  or  other  surfaces,  by  mixing  these  colors 
with  the  solution  above  mentioned,  (bichromate  of  potassa 
and  organic  matter,  etc.) 

"  The  photographic  impression,  on  this  prepared  surface,  is 
produced  by  the  action  of  light  passing  through  a  photo- 
graphic negative,  engraving  or  suitable  object,  or  finally  by 
means  of  the  camera.  It  is  then  washed  by  means  of  a 
sponge  and  an  abundance  of  water.  The  albumen  or  the 
organic  matter  becomes  insoluble  in  the  parts  where  the 
lights  have  acted,  and  the  picture  is  produced  by  the  color 
employed." 

A  second  method  is  described  as  follows  : 

"  In  the  preparation  of  the  papers  I  cover  them  with  a 
concentrated  solution  of  one  of  the  substances  above  men- 
tioned (gum,  gelatine  and  the  like)  in  connection  with  a 
chromate ;  after  drying  I  submit  them  to  the  direct  rays  of 
the  sun  or  to  diffused  light  beneath  a  negative  of  the  object 
to  be  copied.  After  an  exposure,  which  varies  according  to 
circumstances,  I  apply  by  means  of  a  pad  or  a  roller  a  uni- 
form film,  either  of  typographic  or  lithographic  ink,  previ- 
ously diluted,  and  then  I  immerse  the  sheets  in  water.  It 
is  now  that  all  the  parts,  which  have  not  been  impressed  by 
light,  give  up  the  greasy  substance,  while  the  others  retain 
it  hi  proportion  to  the  quantity  of  light  that  has  passed 
through  the  negative." 

The  principle  involved  in  these  two  operations  is  quite 
different,  although  the  result  is  the  same.  In  one  the  film  of 
gelatine,  etc.,  where  it  has  been  exposed  to  the  sun,  has  be- 
come insoluble  in  water,  and  consequently  retains  the  color- 
ing matter  from  being  carried  away  in  the  washing.  In  the 
other  case  the  film  that  has  received  the  impression  of  light, 
has  received  a  new  power,  that  of  adhering  to  the  greasy 
ink  applied  uniformly  to  the  whole  surface,  whilst  the  other 
parts,  having  no  attraction  for  this  ink,  allow  it  to  be  dis- 
solved off  when  floated  on  water. 

All  the  other  carbon  processes,  as  for  instance,  that  ot 
Testud  de  Beauregard,  of  Pouncy,  Chardon,  Salmon  and 
Garnier,  Lafon  de  Camarsac,  and  of  Fargier,  are  mere  modi- 
fications of  Poitevin's  process,  with  but  little  amelioration. 

Testud  de  Beauregard  took  out  a  patent  for  his  process  in 
November,  1858.    It  will  be  unnecessary  to  describe  thi3 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER.  277 


process,  because  it  is  essentially  analogous  to  Poitevin's 
where  he  makes  use  of  printing  ink. 

Pouncxfs  Process. 

Take  a  drachm  of  lampblack,  reduce  it  to  an  impalpable 
powder  and  pass  it  through  a  muslin  sieve  ;  mix  it  inti- 
mately with  half  an  ounce  of  a  concentrated  solution 
of  gum-arabic  and  the  same  quantity  of  a  similar  solu- 
tion of  bichromate  of  potassa.  Lay  on  a  uniform  layer  of 
this  mixture  upon  a  piece  of  a  paper  fixed  on  a  stretcher, 
by  means  of  a  camel's  hair  pencil ;  as  soon  as  it  is  dry,  it 
may  be  exposed  beneath  a  negative  to  the  sun's  rays  for  a 
number  of  minutes,  (from  four  to  eight.)  The  print  is  then 
immersed  in  water,  impression  side  downward,  and  left  for 
five  or  six  hours  in  this  fluid.  Finally  it  is  washed  beneath 
the  tap.  The  gum  and  the  coloring  matter  are  retained  in 
those  parts  that  have  been  impressed ;  whilst  on  the  others 
they  are  dissolved  or  washed  off. 

Pouncxfs  New  Carbon  Process* 

Take  a  sheet  of  tracing  paper,  made  transparent  by  var- 
nish or  oil,  and  coat  it  on  one  side  with  a  solution  of  gela- 
tine. When  dry  it  is  ready  to  receive  a  coating  of  printing 
ink  of  the  consistence  of  cream.  This  ink,  as  far  as  I  have 
been  informed,  consists  of  a  mixture  of  lampblack,  or  some 
similar  material,  together  with  asphaltum  or  bichromate  of 
potassa,  or  with  both.  The  quantity  of  the  latter  is  very 
small  by  reason  of  its  insolubility  in  the  other  ingredients. 
This  ink  is  brushed  over  the  surface  that  has  been  covered 
with  gelatine,  and  is  then  hung  up  to  dry.  This  part  of  the 
operation  has  to  be  performed  in  the  dark-room.  The  paper, 
when  dry,  may  be  preserved  for  months  unchanged,  if  not 
exposed  to  the  light. 

The  next  operation  is  to  expose  the  prepared  paper  be- 
neath a  negative  to  light.  Pouncy  has  availed  himself  of  a 
method  of  exposure  first  suggested  and  used  by  Fargier,  as 
will  be  seen  in  one  of  the  following  jmges.  The  negative  is 
laid  in  the  printing-frame  as  in  the  ordinary  printing  of  pos- 
itives ;  upon  this  place  the  prepared  paper,  but  with  the 
white  surface  upon  the  film  of  the  negative,  and  the  surface 
covered  with  gelatine  and  sensitive  ink  away  from  it  or  on 
the  opposite  side. 

The  light,  therefore,  has  to  pass  both  through  the  nega- 
tive and  the  transparent  paper  before  it  arrives  at  the  sensi 
tive  film.    The  time  of  exposure  is  about  half  an  hour. 


278 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 


Wherever  the  light  impinges  upon  this  film,  it  indurates 
the  ink  and  renders  it  insoluble  in  turpentine  or  benzine.  In 
this  process  the  middle  tones  are  produced  with  great  ac- 
curacy and  beauty. 

After  exposure  there  is  no  apparent  change  in  the  film ; 
but  when  the  paper  is  dipped  in  turpentine  the  soluble  parts 
are  all  dissolved  off.  The  paper  is  next  placed  in  a  second 
bath  of  turpentine  where  the  lights  are  thoroughly  cleansed  of 
ink. 

The  paper  is  then  taken  out  and  dried.  The  paper  being 
transparent,  the  picture  is  seen  through  it,  and  then  regard- 
ed as  a  true  picture,  free  from  inversion.  These  prints  can 
be  used  as  transparencies,  or  can  be  transferred  to  cardboard 
or  stone.  In  the  former  case  they  look  like  wood-cuts  or  en- 
gravings, combining  at  the  same  time  all  the  beauty  of  the 
photograph. 

This  discovery  of  Pouncy's  has  been  published  without 
the  necessary  details,  just  as  these  sheets  are  passing  through 
the  press ;  but  if  the  results  are  as  stated  by  good  authori- 
ties, it  may  be  regarded  as  the  great  discovery,  not  only  01 
the  year,  but  of  the  age.  Neither  silver  nor  gold  is  re- 
quired in  the  process — the  prints  appear  in  printing  ink 
after  developing,  fixing,  and  washing  in  turpentine. 

Processes  of  Salmon  and  Gamier, 

For  one  of  these  processes  a  part  of  the  Luynes  second 
prize  was  assigned  to  the  authors  in  1858.  Their  other  pro- 
cess was  not  brought  into  competition,  although  it  was  pa- 
tented. (Poitevin  took  the  first  gold  prize.)  In  both  pro- 
cesses a  transparent  positive  is  employed  instead  of  a  nega- 
tive. 

No.  1 .  —  Dissolve  thirty  drachms  of  loaf-sugar  in  thirty 
Irachms  of  water,  then  add  seven  drachms  and  a  half  of 
neutral  bichromate  of  ammonia,  pulverized  and  dissolved 
in  a  mortar.  To  this  mixture  add  ten  drachms  of  the 
white  of  egg  previously  well  beaten  up  together  with 
a  few  grains  of  the  bichromate.  As  soon  as  all  these 
ingredients  have  been  very  intimately  mixed,  the  solution 
is  passed  through  a  linen  filter  for  use.  In  the  mean 
while  the  paper  is  fixed  on  a  board  by  means  of  tacks, 
and  then  brushed  over  with  the  above  mixture.  Take  care 
to  use  of  the  mixture  only  just  enough  to  cover  the  surface 
in  order  thus  to  obviate  streaks  and  other  similar  imperfec- 
tions. The  paper  is  then  removed  and  dried  before  the  fire, 
taking  care  not  to  bring  it  too  near,  and  to  present  the 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER.  279 


posterior  side  to  the  heat.  This  part  of  the  operation  is  soon 
finished.  It  is  then  exposed  beneath  a  positive  to  the  rays  of 
the  sun  for  fifteen  or  twenty  minutes.  After  the  expiration 
of  this  time  the  image  is  quite  visible ;  the  paper  is  again  heat- 
ed befor  3  the  fire,  which  appears  to  continue  the  action  of  light, 
and  thus  becomes  the  means  of  modifying  the  intensity  of 
the  shades.  It  is  now  fixed  a  second  time  upon  the  board, 
and  fine  ivory  black  is  brushed  over  the  surface  with  a  fiat, 
moderately  soft  and  flexible  camel's  hair  brush.  The  film 
of  ivory  black  is  afterward  uniformly  spread  by  means  of  a 
soft  pad  of  cotton  all  over  the  surface,  after  which  the  paper 
is  detached  from  the  board  and  presented  for  a  few  seconds 
to  the  fire.  This  being  done,  the  paper  is  cautiously  immersed 
in  water,  picture-side  upward,  and  left  there  for  a  quarter 
of  an  hour,  moving  it  about  gently  at  intervals.  As  soon  as 
it  is  supposed  that  the  soluble  portions  of  the  bichromate 
have  been  removed  by  the  water,  the  paper  is  withdrawn. 
Finally,  in  order  to  improve  the  whites,  the  paper  is  im- 
mersed in  a  bath  containing  ten  ounces  of  water  and  half  an 
ounce  of  concentrated  sulphurous  acid.  This  operation  has 
to  be  performed,  in  like  manner  with  the  preceding,  with 
great  care,  otherwise  the  coloring  matter  is  liable  to  be  carried 
off*  from  the  parts  which  are  insoluble,  for  the  film  does  not 
adhere  with  much  tenacity.  The  object  of  this  final  immer- 
sion is  to  remove  a  number  of  yellow  and  gray  patches  in 
the  lights  ;  with  the  greatest  care,  however,  it  is  very  difficult 
to  get  rid  of  numerous  small  particles  of  charcoal  imbedded 
as  it  were  in  the  porous  structure  of  the  paper.  After  this 
operation  the  paper  is  taken  and  dried. 

Sulphurous  acid  may  be  prepared  for  the  preceding  oper- 
ation, by  heating  a  mixture  of  sulphuric  acid  and  small 
fragments  of  wood,  such  as  chips  or  matches,  in  a  retort. 
The  vapor  thus  produced  is  sulphurous  acid,  which  car.  be 
condensed  in  cold  rain-water  to  saturation. 

No.  2. — In  the  second  process  a  thick  solution  of  citrate 
of  iron  is  spread  evenly  with  a  soft  linen  pad  over  the  surface 
of  a  sheet  of  satin  paper.  The  paper  is  then  dried  in  the 
dark-room.  It  is  next  exposed  beneath  a  transparent  posi- 
tive from  ten  to  thirty  minutes  to  the  rays  of  the  sun,  by 
which  an  image  is  made  apparent.  This  is  intensified  or 
made  more  vigorous  by  the  following  application.  Fix  the 
paper  on  a  board  with  tacks  and  then  with  a  cotton  pad  dab 
the  surface  over  uniformly  with  an  impalpable  powder  of 
carbon  or  any  other  color.  At  first  no  change  is  apparent, 
but  by  breathing  upon  the  surface,  those  parts  that  have  not 


280 


PRINTING  WITHOUT  THE  SALTS  OF  SIL^R. 


been  impressed  by  light,  beingmore  or  lesshygrometricin  pro- 
portion to  the  actinic  action,  attract  the  humidity  and  at  the 
same  time  the  coloring  material,  which  exhibits  the  image. 
The  parts  through  which  light  has  penetrated,  being  no 
longer  deliquescent,  or  at  least  only  partially  so,  reject  the 
carbonaceous  materials,  and  these  are  swept  away  together 
with  the  unaltered  citrate  in  the  process  of  washing  and 
fixing.  The  prints  are  afterward  dried  and  varnished  if 
thought  necessary.  The  addition  of  sugar  to  the  citrate  in 
this  process  is  recommended  by  Poitevin. 

All  these  processes  are  more  or  less  defective,  producing 
prints  devoid  of  the  middle  tones.  This  arises  from  the 
circumstance  that  the  image  is  in  general  a  mere  surface 
picture,  and  especially  as  regards  the  middle  tints.  In  the 
washing,  therefore,  these  are  apt  to  be  annihilated  together 
with  the  soluble  film  beneath  them.  This  defect  had  been 
noticed  and  the  cause  assigned  by  Laborde  as  well  as  by 
Poitevin  ;  and  it  is  probable  that  Fargier  eliminated  his  pro- 
cess on  the  hints  thus  published.  The  difference  in  his  mode 
of  manipulating  consists  essentially  in  separating  the  film 
containing  the  image  from  the  glass  upon  which  it  was  form- 
ed, and  in  fixing  it  on  a  piece  of  gelatinized  paper  the  other 
side  up.  The  chemical  and  actinic  part  of  the  operation  re- 
mains the  same  as  in  Poitevin's. 

Fargier1  s  Process. 

Make  a  mixture  of  two  drachms  of  white  gelatine  dissolv- 
ed in  two  ounces  and  a  half  of  water,  and  fifteen  grains  of 
lampblack,  (previously  washed  with  carbonate  of  soda,  and 
afterward  with  hydrochloric  acid,  in  order  to  remove  all 
fatty  or  resinous  matter ;)  to  this  mixture  add  few  drops 
ef  ammonia  in  order  to  decompose  the  alum  contained  in 
the  gelatine  and  finally  fifteen  grains  of  bichromate  of 
potassa.  The  mixture,  when  the  ingredients  are  thor- 
oughly dissolved,  is  filtered  through  a  linen  cloth,  and  after 
it  is  made  hot,  it  is  poured  upon  a  properly  cleaned  glass, 
and  the  films  dried  by  a  gentle  heat. 

The  glass,  thus  prepared,  is  exposed  for  a  few  seconds  to 
the  light,  and  then  beneath  a  negative  to  the  rays  of  the  sun. 

The  first  exposition  to  light  for  a  few  seconds  is  to  rendei 
the  whole  surface  of  the  gelatine  slightly  insoluble.  The 
second  exposure  beneath  a  negative  produces  an  insolubility 
more  or  less  deep  according  to  the  luminous  intensity  and 
its  duration.  It  will  be  easily  conceived  that  the  two  sur- 
iaces  of  the  gelatine  film,  that  is,  the  upper  s  urface  an<?  the 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER.  281 


one  adhering  to  the  glass,  are  in  very  different  conditions, 
the  former  being  almost  totally  soluble,  excepting  here  and 
there  where  the  intensity  of  the  rays  has  penetrated  the  whole 
substance  ;  whereas  the  exterior  surface,  as  before  remarked, 
is  insoluble.  The  parts  between  these  surfaces  are  more  or 
less  soluble  according  to  the  quantity  and  intensity  of  the 
light  that  has  passed  through  the  negative.  It  will  be  seen, 
therefore,  from  these  conditions  of  things,  that  the  operation 
if  washing,  in  order  to  be  effectual,  ought  to  be  performed 
on  the  under  surface.  The  film  consequently  is  removed  from 
the  glass  and  transferred  in  the  following  manner  : 

Flow  the  film  on  the  glass  plate  with  two  coats  of  collodion, 
and  then  immerse  it  in  a  dish  of  lukewarm  water.  The  col- 
lodion will  soon  be  detached  together  with  the  gelatine  film, 
which  will  float  in  the  water.  The  film  is  allowed  to  remain 
until  all  the  soluble  parts  are  dissolved  off,  together  with 
the  coloring  matter  which  they  contain.  By  this  mode  of 
proceeding  the  most  delicate  half-tones  remain  attached  to 
the  collodion,  and  the  image  is  brought  out  very  perfectly. 
Whilst  in  this  condition  in  the  water  a  piece  of  paper  already 
prepared  with  gelatine  is  brought  carefully  beneath  the  float- 
ing film  and  then  lifted  out  of  the  water  and  stretched  upon 
a  board.  The  film,  carefully  adjusted  on  the  gelatinized  sur- 
face of  the  paper,  soon  adheres  to  it,  and  may  thus  be  dried. 

Carbon  Processes  with  the  Salts  of  Iron. 
Without  recapitulating  all  the  various  processes  arising 
out  of*  the  use  of  the  salts  of  iron,  I  may  here  mention  that 
Poitevin  has  employed  the  gallate  of  iron  and  the  sesqui- 
chloride ;  and  that  others,  following  in  his  steps,  have  been 
more  or  less  successful  in  the  same  domain  of  experimenta- 
tion. I  will  give  two  examples  only,  and  refer  the  reader 
for  more  ample  information  to  Poitevin's  interesting  treatise. 

.No.  1. — Process  with  Sesquichloride  of  Iron  and  Tartaric 

Acid. 

Make  two  solutions  as  follows : 

No  1    \  Sesqui  chloride  of  iron,    ....  5^  drachms. 

(  Water,   15  drachms. 

2    (  Tartaric  acid,   2  drachms. 

\  Water,    ....        ....  15  drachms. 

Filter  each  solution  separately,  then  mix  and  add  two 
ounces  and  a  half  more  water.  Keep  the  solution  in  the 
dark,  and  use  it  until  exhausted. 

The  image  with  carbon  or  any  other  colored  and  inert 


282  PRINTING  WITHOUT  THE  SALTS  OF  SILVEK. 


powder  is  formed  on  glass.  For  this  purpose  Poitefin  re« 
commends  such  glass  as  is  used  for  stereoscopic  slides,  being 
ground  on  one  side.  If  the  glasses  have  been  used  before, 
they  are  cleaned  by  the  ordinary  means  recommended. 
Each  glass  is  then  flowed  with  the  sensitizing  solution  just 
prepared,  in  the  same  way  as  with  collodion  or  albumen, 
and  the  excess  is  poured  off  at  each  corner.  They  are  then 
reared  on  one  corner  on  pieces  of  bibulous  paper,  inclining 
at  an  angle  of  60°,  with  the  sensitized  surface  downward. 
It  is  better  to  dry  the  plates  by  rearing  them  up  near 
some  heated  surface,  otherwise  the  operation  of  desiccation 
will  be  very  tedious.  This  operation  must  be  performed  in 
the  dark-room.  The  property  of  the  dry  plates  is  this: 
by  the  influence  of  light  they  become  hydroscopic.  The 
plates  so  prepared  will  keep  for  months  in  boxes,  as  was 
to  be  expected,  inasmuch  as  the  persalts  of  iron  have  a 
tendency  in  the  dark  rather  to  peroxidize  than  to  be  reduced 
to  protosalts. 

A  plate  is  exposed  beneath  an  ordinary  negative  varnished 
with  copal  dissolved  in  alcohol ;  all  other  varnishes,  such  as 
those  prepared  with  benzine,  gum,  gelatine,  etc.,  would  be 
injurious.  The  film  of  the  prepared  glass  and  of  the  negative 
are  in  juxtaposition,  and  are  placed  together  with  great  care. 
The  time  of  exposure  is  about  the  same  as  in  the  common 
printing  process.  This  has  to  be  learned  by  practice  ;  it  is 
better  to  give  too  much  time  than  too  little,  because  the  de- 
velopment can  be  stopped  as  soon  as  the  image  has  sufficient- 
ly appeared.  When  taken  from  the  printing  frame  the  picture 
is  already  visible,  white  upon  a  yellow  ground.  It  is  exposed 
in  the  dark-room  to  the  influence  of  the  air,  when  it  will  be 
found  that  all  those  parts  that  have  received  the  luminous 
action  will  become  moist.  In  a  few  minutes  the  film  will  be 
ready  to  receive  the  first  application  of  the  carbonaceous  or 
other  inert  colored  material. — By  putting  away  the  plates 
when  taken  from  the  printing  frame  in  well-closed  boxes, 
the  development  may  be  postponed. — The  development  is 
effectuated  by  dipping  a  very  soft  camel's  hair  pencil  in  the 
fine  impalpable  powder  and  then  dabbing  or  rubbing  it  gent- 
ly over  the  surface  of  the  impressed  plates ;  the  image  will 
soon  begin  to  appear,  the  coloring  material  adhering  only  to 
those  parts  that  have  become  hydroscopic  by  the  action  of 
the  light,  and  consequently  in  proportion  to  the  luminous 
impression.  In  general  the  half-tones  do  not  appear  by  the 
first  application  of  the  powder,  and  it  is  better  when  this 'is 
so ;  for  if  the  plate  took  up  the  color  too  quickly,  it  would 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER.  283 

be  a  sign  that  the  exposure  had  been  too  long.  A  second 
application  of  the  powder  is  made,  and  then  a  third,  and  so 
on,  until  the  image  is  brought  out  in  perfect  harmony  of 
light  and  shade.  The  operation  may  be  stopped  midway 
without  any  injury  to  the  final  development,  which  may  be 
completed  at  any  convenient  time.  It  is  very  easy  to  follow 
the  progress  of  development  by  placing  the  plate  image  side 
downward  on  a  sheet  of  paper,  or  by  regarding  it  by  trans- 
mitted light ;  but  seen  so,  it  is  always  more  feeble  than  by 
reflected  light.  It  is  also  easy  to  accelerate  certain  portions 
which  are  slow  in  appearing ;  all  that  is  required  is  to  moist- 
en them  with  the  breath,  and  then  go  over  the  parts  with  the 
pencil  dipped  in  the  carbonaceous  powder.  As  soon  as  the 
image  is  perfect,  it  may  be  retained  on  the  plate  by  means 
of  a  coat  of  varnish,  and  thus  be  used  as  a  transparent  posi- 
tive, without  any  washing  or  fixing.  If  instead  of  lampblack 
or  vegetable  colors,  metallic  oxides  or  enamel  powders  were 
to  be  applied  to  the  sensitized  glass  plate,  these  coloring  sub- 
stances may  be  melted  in  a  muffle,  which  communicates  to  the 
surface  of  the  glass  plate  a  perfectly  unalterable  picture,  sim- 
ilar to  glass-painting ;  the  same  mode  of  operation  may  be 
applied  to  plates  of  porcelain.  In  case,  however,  it  is  required 
to  transfer  the  print  to  paper,  the  operation  may  be  perform- 
ed either  immediately  or  a  long  time  afterward. 

To  transfer  the  Carbon  Print  from  Glass  to  Paper. 

This  operation  is  extremely  simple,  and  presents  no  diffi- 
culty. Coat  the  film,  containing  the  picture,  with  common 
plain  collodion,  of  a  consistence  suitable  for  photographic 
purposes,  then  immerse  the  plate  in  water  until  the  oily  as- 

[>ect  of  the  film  has  disappeared.  Next  pour  upon  the  col- 
odion  surface  water  acidulated  with  hydrochloric  acid  ; 
repeat  the  operation  two  or  three  times.  The  film  immedi- 
ately in  contact  with  the  glass  is  rendered  soluble  in  water 
by  means  of  the  acid,  and  the  adherence  of  the  collodion  to 
the  glass  is  at  the  same  time  destroyed.  The  acid  is  then 
thoroughly  removed  by  washing  in  several  waters,  and  then 
a  piece  of  paper,  covered  with  a  layer  of  gelntine  on  one  side 
and  previously  moistened,  is  placed  upon  the  collodion  and 
brought  into  contact  with  it  by  means  of  a  large,  broad  and 
soft  pencil,  which  is  moved  over  it  in  all  directions.  As  soon 
as  the  contact  is  complete  and  all  bubbles  of  air  have  been 
removed,  the  whole  is  left  to  dry  spontaneously.  In  the  act 
of  drying  the  gelatinized  paper  separates  from  the  glass  of 
itself,  carrying  with  it  the  film  of  collodion  in  firm  adhesion 
14 


284  FEINTING  WITHOUT  THE  SALTS  OF  SILVER. 


to  the  picture.  All  that  now  remains  to  be  done  is  to  var- 
nish the  surface.  Copal  varnish  is  suitable  for  this  purpose, 
because  it  lies  upon  the  surface  of  the  image  without  pene- 
trating the  film  of  collodion  or  gelatine,  and  consequently 
never  arrives  at  the  paper  beneath.  The  prints,  thus  obtain- 
ed, have  a  very  delicate  and  velvety  appearance,  the  only 
drawback  being  that  of  lateral  inversion  like  the  negative, 
unless  the  latter  has  been  specially  prepared  beforehand. 
But  the  picture  can  be  produced  without  any  lateral  inver- 
sion, not  only  by  having  a  negative  in  the  right  conditions, 
but  by  the  following  somewhat  complicated  manipulation, 
although  equally  as  easy  as  the  preceding.  In  this  case, 
the  collodion  is  applied  as  before,  the  immersion  in  water 
and  the  flowing  with  acidulated  water  are  performed,  and 
then  a  piece  of  moistened  paper,  smaller  in  size  than  the 
plate,  is  brought  into  contact  with  the  collodion  film,  in  the 
same  way  as  the  gelatinized  paper  was  made  to  adhere. 
The  border  of  film  all  round  the  paper  is  now  raised  and 
folded  over  the  edges  of  the  paper,  which  when  raised  with 
caution  carries  the  whole  detached  film  from  the  glass.  A 
piece  of  paper  covered  with  gelatine  and  larger  than  the  plate 
is  now  moistened,  upon  this  the  detached  print  is  brought 
into  contact,  pressed  into  perfect  adhesion  by  means  of  the 
soft  brush,  and  then  the  borders  of  the  film  around  the  edges 
of  the  first  paper  are  folded  back,  when,  seizing  an  angle 
of  the  first  paper,  it  is  easily  raised  from  the  collodion  film. 
The  picture  now  is  no  longer  inverted,  and  is  besides  fixed, 
the  coloring  matter  or  image  proper  lying  protected  between 
two  films,  one  of  collodion  and  the  other  of  gelatine.  With 
a  tenacious  collodion  this  operation  of  double  transfer  is  al- 
ways successful ;  it  takes  in  fact  longer  to  describe  it  than  to 
perform  it  ;  as  to  the  simple  transfer,  it  always  succeeds, 
whatever  may  be  the  quality  of  the  collodion. 

This  process,  after  all,  is  very  simple  and  almost  always 
certain;  besides  this,  it  entails  but  little  expense  and  re- 
quires less  delicacy  of  manipulation  than  other  photographic 
processes. 

For  vitrification  or  enamel  operations,  it  possesses  a  great 
advantage  arising  from  the  facility  of  folding  the  collodion 
film,  retaining  the  picture  upon  curved  as  well  as  upon  plain 
surfaces. 

Another  property  of  the  surfaces  prepared  with  the  sesqui- 
chloride  of  iron  and  tartaric  acid  is  this  :  fatty  substances, 
such  as  printing  inks,  applied  after  the  luminous  impression 


PRINTING  WITHOUT  THE  SALTS  01  SILVER. 


285 


through  a  negative,  adhere  only  to  those  parts  that  have  not 
been  modified  by  light. 

Almost  all  vegetable  colors  may  be  used  in  this  process ; 
it  will  be  evident  therefore  that  pictures  resisting  all  change 
from  the  atmosphere  or  from  time,  may  be  obtained  of  any 
color  that  may  please  the  fancy. 

JPri?iting  directly  on  Paper  by  means  of  the  Sesquichloride 
of  Iron  and  Tartaric  Acid. 

This  is  a  new  process  of  Poitevin's.  Five  or  six  parts  of 
gelatine  are  dissolved  in  a  hundred  parts  of  water ;  this  so- 
lution is  colored  with  a  sufficient  quantity  of  lampblack  or 
any  other  inert  color.  Each  sheet  of  paper  is  floated  on  this 
solution,  which  is  kept  lukewarm  on  a  water-bath.  By  this 
means  a  very  uniform  film  of  color  is  communicated  to  one 
side  of  the  paper,  which  is  afterward  placed  flat  on  a  hori- 
zontal surface  with  the  colored  side  uppermost,  and  allowed 
to  dry  spontaneously.  In  this  way  a  large  number  of  sheets 
may  be  prepared  beforehand. 

In  order  to  sensitize  them  they  are  immersed  in  a  bath 
containing  a  solution  of  sesquichloride  of  iron  and  tartaric 
acid  in  the  proportion  of  ten  parts  of  the  sesquichloride  01 
iron,  one  hundred  parts  of  water  and  three  parts  of  tartaric 
acid.  The  papers  are  then  allowed  to  dry  in  the  dark.  By 
this  treatment  the  film  of  gelatine  has  become  completely 
insoluble,  even  in  boiling  water. 

These  films  receive  the  actinic  impressions  through  a  trans- 
parent positive ;  and  in  the  parts  where  the  light  acts,  the 
film  becomes  soluble  in  hot  water  proceeding  from  the  sur- 
face of  the  film  in  contact  with  the  transparent  positive. 

After  the  paper  has  been  in  this  way  exposed  to  the  sun, 
if  the  positive  is  not  very  intense,  (which  is  preferable  in  this 
kind  of  print,)  it  is  immersSd  in  hot  water;  then  all  the 
parts  that  have  undergone  the  solar  influence  are  dissolved 
in  proportion  to  the  quantity  of  light  that  has  permeated 
the  glass  positive.  In  the  places  which  correspond  with  the 
lights  of  the  positive,  the  blackened  or  colored  surface  is 
dissolved  to  the  surface  of  the  paper,  and  will  leave  perfect 
whites ;  whereas  in  the  half-tints,  only  a  certain  portion  of 
the  film  will  disappear,  proceeding  from  the  surface,  and 
these  half-tones  will  be  reproduced  by  the  greater  or  less 
thickness  of  the  film  of  gelatine  remaining  insoluble.  Now 
as  this  part  is  in  immediate  contact  with  the  surface  of  the 
paper,  it  can  not  be  carried  away  in  washing.  As  to  those 
parts  of  the  positive  which  are  completelv  black,  they  will 


286  PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 


be  produced  by  the  total  thickness  of  the  primitive  film.  All 
that  is  required  to  finish  the  print  is  to  allow  it  to  dry,  and 
then  to  wash  it  in  acidulated  water  in  order  to  get  rid  of  the 
salts  of  iron,  afterward  to  pass  it  through  several  waters, 
and  finally  to  allow  it  to  dry  spontaneously. 

Photographic  Engraving. 
It  is  a  curious  fact  that  experiments  in  photographic  en- 
graving gave  rise  to  photography  itself.  The  idea,  the  most 
prominent  in  the  mind  of  Nicephore  Niepce,  when  he  com- 
menced his  indefatigable  researches  in  1813,  was  not  only  to 
fix  the  image  obtained  by  the  camera  obscura  on  a  plate  of 
metal,  but  to  convert  this  plate  into  an  engraving  from  which 
to  receive  prints  by  the  press.  After  the  partnership  con- 
cluded between  Niepce  and  Daguerre,  this  idea  appears  to 
have  been  abandoned;  and  an  early  death  removed  the 
former,  the  real  originator  of  much  that  is  valuable  in  pho- 
tography, before  he  perfected  the  process  which  he  left  us. 
This  process,  together  with  a  great  deal  that  is  interesting 
in  photographic  engraving,  will  be  found  at  length  in  a  small 
pamphlet  published  by  his  indefatigable  nephew,  Niepce  de 
Saint- Victor,  the  Traite  Pratique  de  Gravure  Heliograph- 
ique,  in  1856. 

The  various  ways  that  have  been  taken  to  come  to  one 
and  the  same  result,  that  of  obtaining  a  metallic  plate,  re- 
sembling an  engraved  plate,  from  which  to  receive  prints 
exactly  in  the  same  way  as  with  the  engraved  plate,  take 
their  origin  either  from  the  Iodo-mercurio-type  or  plated  cop- 
per of  Donne,  the  bichromotype  of  Talbot,  or  the  asphalto- 
type  of  Nicephore  Niepce,  if  I  may  thus  be  allowed  to  create 
new  names  to  represent  these  three  classes.  Without  adher- 
ing to  historical  dates,  I  will  simply  recount  what  has  been 
accomplished  in  each  class.  • 

Engraving  on  the  Daguerreotype  Plate. 

The  first  attempts  that  were  made  to  convert  the  daguer 
veotype  into  an  engraved  plate  by  an  etching  liquid,  were 
tnose  of  Dr.  Donne.  He  first  went  round  the  edge  of  the 
plate  with  a  varnish  or  wax,  making  a  ledge  so  as  to  retain 
the  etching  fluid.  This  fluid  consisted  of  aquafortis  diluted 
with  four  parts  of  water,  which,  when  poured  upon  the  plate 
immediately  after  the  image  was  fixed,  but  not  gilt,  attacked 
the  silver  parts,  without  injuring  or  altering  the  whites.  As 
'soon  as  the  etching  was  supposed  to  have  advanced  far 
enough,  the  plate  was  well  washed,  and  the  varnish  or  wax 
removed  from  the  edges.    It  was  then  ready  to  print  from. 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER.  287 

The  specimens  obtained  by  the  engraver's  press  from  such 
plates  were  not  very  satisfactory ;  and  the  softness  of  the 
silver  film  precluded  the  possibility  of  printing  more  than  a 
few  dozen  from  the  same  plate. 

Process  of  Fizeau. 

This  process  is  similar  to  that  of  Donne,  but  it  proceeds 
further,  and  thus  overcomes  two  very  great  imperfections  in 
Donne's  plates  :  the  want  of  depth  in  the  parts  etched,  and 
the  extreme  softness  of  the  silver  film.  I  will  give  the  pro- 
cess as  described  by  the  originator  : 

"  A  mixed  acid,  composed  of  nitric,  nitrous  and  hydro- 
chloric, (the  last  two  may  be  replaced  by  nitrite  of  potassa 
and  common  salt,)  is  endowed  with  the  requisite  properties, 
which  is  common  to  a  solution  of  bichloride  of  copper,  but 
in  a  manner  less  perfect. 

"  If  a  daguerreotype,  whose  surface  is  very  pure,  be  sub- 
mitted to  the  action  of  this  acid,  especially  when  hot,  the 
white  parts  are  not  altered,  while  the  blacks  are  attacked 
with  the  formation  of  chloride  of  silver,  which  adheres  to 
the  surface  and  prevents  any  further  action  of  the  acid  by 
reason  of  its  insolubility. 

"Ammonia  is  then  poured  upon  the  plate,  which  removes 
the  film  of  chloride,  and  thus  presents  a  fresh  surface  to  the 
action  of  the  acid.  By  this  means  the  depth  of  the  shades 
can  be  increased. 

"  By  operating  in  this  way  for  several  times,  the  daguerreo- 
type becomes  converted  into  an  engraved  plate  of  great 
perfection,  but  in  general  not  possessed  of  sivfficient  depth, 
so  that  the  prints  on  paper  are  not  vigorous  enough.  It  has 
been  found  necessary,  therefore,  to  adopt  other  means  of  in- 
creasing the  depth  of  the  shades.  This  operation  consists  in 
gilding  the  prominent  parts  or  the  lights  of  the  engraving, 
and  to  leave  the  silver  in  the  etched  parts  intact ;  by  which 
means  the  depth  of  the  etching  can  be  increased  afterward 
by  a  simple  solvent  of  silver. 

"  In  order  to  obtain  this  result,  the  plate  engraved  as  just 
described  is  rubbed  over  with  a  drying  oil,  as  for  instance 
linseed  oil,  then  wiped  in  the  manner  of  copper-plate  print- 
ers. In  this  way  the  oil  remains  in  the  cavities  alone  and 
forms  a  varnish  which  soon  dries. 

"Gold  is  next  deposited  by  galvanism  upon  all  the  parts  of 
the  plate  excepting  those  filled  with  the  linseed  varnish, 
which  is  afterward  removed  by  caustic  potassa.  The  result 
of  this  is  that  all  the  prominent  parts  of  the  plate  are  protected 


288  PKIJSTTTN G  WITHOUT  THE  SALTS  OF  SILVER. 


by  a  film  of  gold ;  whereas  the  excavated  parts  present  de- 
nuded silver. 

"  It  is  now  easy  by  means  of  nitric  acid  to  act  upon  these 
hollow  parts  alone,  and  thus  increase  the  depth  ad  libitum. 
Previous  to  this  treatment,  however,  the  plate  is  covered  by 
what  is  denominated  by  engravers  the  resin-grain,  which 
produces  in  the  metal  those  numerous  inequalities  denomi- 
nated aqua-tinta  granulations. 

"From  the  result  of  these  two  operations  the  daguerreo- 
type plate  is  transferred  into  an  engraved  plate  resembling 
the  aqua-tinta  plates,  which  like  these  is  in  a  condition  by 
impression  to  furnish  a  number  of  prints. 

"  But  since  silver  is  a  very  soft  metal,  the  number  of  im- 
pressions would  be  very  limited,  if  some  very  simple  means 
were  not  devised  to  remedy  the  speedy  destruction  of  the 
photographic  plate  when  submitted  to  the  operations  of  the 
press. 

"  This  end  is  attained,  previous  to  handing  the  plate  over 
to  the  printer,  by  covering  its  surface  with  a  film  of  cop- 
per by  the  electrolitic  process.  In  this  way  it  is  evident 
that  the  film  of  copper  alone  bears  the  wear  and  tear  pro- 
duced by  the  labor  of  the  pressman.  If  this  film  should 
happen  to  be  damaged  to  any  considerable  degree,  it  may 
be  entirely  dissolved  off  by  means  of  a  dilute  acid,  without 
injuring  the  silver  on  which  it  is  deposited,  when  the  plate 
may  again  be  covered  with  copper,  and  rendered  as  good 
as  new," 

Process  of  Talbot. 
Plates  of  copper,  steel  or  zinc  are  employed  in  this  pro- 
cess. These  are  first  washed  over  with  a  dilute  solution  of 
sulphuric  acid  in  order  to  remove  the  film  of  oxide,  then  well 
rubbed  with  a  mixture  of  carbonate  of  soda,  and  well  dried. 
A  solution  of  bichromate  of  potassa  and  gelatine  is  then 
Ah  wed  over  the  surface,  and  dried  by  the  application  of  heat 
i)  :/til  the  film  assumes  a  beautiful  yellow  color.  This  opera- 
lion  is  performed  in  the  dark-room. 

^    1      j  Gelatine,  1  drachm. 

JN0*1,    \  Water,  2  J  ounces. 

No.  2,    ■{  Saturated  solution  of  bichromate  of  potassa,  .    4  drachms. 

Mix  the  two  solutions  and  filter.  The  mixture  will  keep 
for  some  time.  In  summer  it  is  sufficiently  fluid ;  but  in 
winter  it  requires  to  be  warmed  before  it  is  flowed  upon  the 
plates.  It  must  be  preserved  in  a  dark  place.  The  propor- 
tions above  given  are  found  to  work  well,  but  they  may  be 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER.  289 


changed,  however,  without  altering  the  result.  The  color 
of  the  film  is  pale  yellow  and  generally  bordered  with  nar- 
row fringes  of  prismatic  colors.  If  the  whole  surface  i» 
covered  with  this  prismatic  appearance,  it  indicates  that  the 
film  is  very  thin,  perhaps,  if  any  thing,  too  much  so  for  suc- 
cessful manipulation. 

The  transparent  positive  or  other  object  is  now  placed  in 
the  printing  frame  and  the  prepared  plate  upon  it.  An  al- 
bumen photograph  is  the  best  adapted  for  such  operations, 
because  the  film  is  the  least  liable  to  be  damaged.  The  two 
films  are  in  juxtaposition.  An  exposure  of  two  or  three 
minutes  to  the  rays  of  the  sun  will  produce  a  picture  which 
will  appear  yellow  on  a  brownish  background.  A  longer 
exposure  is  required  in  diffused  light ;  the  amount  of  which 
will  have  to  be  modified  by  experience. 

The  next  operation  consists  in  covering  the  film  of  the 
plate  when  removed  from  the  printing-frame  with  very  fine 
copal  or  resin  powder.  This  part  of  the  work  has  to  be  per- 
formed with  great  care  and  uniformity.  It  is  frequently  ef- 
fected by  placing  a  heap  of  the  finely  pulverized  material  on 
the  bottom  of  the  box  and  then  with  a  pair  of  bellows  to 
make  a  cloud  of  the  dust  in  which  the  plate  is  placed.  The 
object  of  this  operation  is  to  communicate  to  the  plate  the 
aqua-tinta  granulation.  If  the  film  of  copal  or  resin  be  too 
thick,  the  etching  fluid  will  not  be  able  to  penetrate  to  the 
metallic  plate  beneath.  The  plate  thus  covered  with  the 
powder  is  heated  over  an  alcohol  lamp  in  order  to  melt  the 
copal.  The  fusion  is  known  to  be  effected  by  a  change  in 
the  color.  The  plate  is  then  allowed  to  cool.  The  ordinary 
way  of  producing  an  aqua-tinta  foundation  is  to  project  the 
resinous  powder  on  the  denuded  surface  of  the  metal ;  in 
this  case  it  is  on  the  surface  of  the  gum  itself,  and  it  is  found 
to  act  well. 

The  etching  fluid  is  prepared  as  follows  :  Saturate  hydro- 
chloric acid  with  sesquioxide  of  iron  by  means  of  heat.  The 
solution  is  filtered  and  evaporated  until  when  cooled  it  be- 
comes a  concrete  mass,  which  is  preserved  in  well-stoppered 
bottles.  It  is  a  very  deliquescent  salt.  With  this  salt  pre- 
pare three  solutions  in  the  following  manner : 

No.  1.  Saturated  solution  of  sesquichloride  of  iron  in 
water.  * 

No.  2.  Contains  five  or  six  parts  of  No.  1  to  one  of  water. 

No.  3.  Contains  equal  portions  of  No.  1  and  water. 

The  stronger  the  solution,  the  less  effective  in  etching ; 
the  right  strength  can  be  learned  only  by  experience.  Make 


290 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 


a  trial  as  follows  :  Pour  a  small  quantity  of  No.  2  upon  the 
plate  and  spread  it  with  a  camel's  hair  pencil.  It  is  not 
necessary  to  have  an  elevated  border  of  wax  around  the 
plate,  because  but  a  very  small  quantity  of  fluid  is  used,  and 
there  is  no  danger  of  its  flowing  over  the  edges  of  the  plate. 
The  etching  fluid  penetrates  the  gelatine  where  the  light  has 
not  acted,  and  this  penetration  is  in  proportion  to  the  defi- 
ciency of  the  luminous  action.  On  this  remarkable  property 
is  founded,  in  a  great  measure,  the  art  of  photographic  en- 
graving. After  a  minute  or  so,  the  engraving  begins  to  show 
itself  by  turning  dark,  brown  or  black  ;  and  soon  the  effect 
extends  over  the  whole  plate.  The  details  of  the  picture 
appear  with  great  rapidity  in  each  part.  This  rapidity  must 
not  be  too  great,  and,  where  there  is  a  tendency  in  this  di- 
rection, the  progress  of  the  etching  must  be  impeded  before 
it  has  acquired  a  sufficient  depth,  (which  requires  an  action 
of  a  few  minutes'  duration.)  If  in  these  preliminary  exper- 
iments it  be  found  that  this  tendency  prevails,  the  solution 
No.  2  has  to  be  modified  by  the  addition  of  a  portion  of  the 
saturated  solution  No.  1,  before  No.  2  can  be  employed  in 
the  etching  of  a  fresh  plate  ;  but  if,  on  the  contrary,  the 
engraving  fails  to  appear  after  the  lapse  of  a  minute,  or 
if  it  commences  but  proceeds  too  slowly,  it  is  a  sign  that  the 
liquid  No.  2  is  too  strong  or  too  near  its  saturation.  This 
deficiency  is  corrected  by  adding  a  little  water  before  it  is 
employed  for  a  second  plate.  In  making  this  correction  the 
operator  must  not  forget  that  a  small  quantity  of  water  often 
produces  a  great  difference  and  causes  the  etching  to  pro- 
ceed very  quickly.  As  soon  as  the  strength  of  No.  2  has 
been  appropriately  graduated,  which  in  general  requires 
three  or  four  experimental  trials,  it  may  afterward  be  em- 
ployed with  safety.  In  this  case  the  plate  is  flowed  as  before 
indicated,  and  the  operation  proceeds  until  all  the  details 
appear  and  present  a  satisfactory  aspect  to  the  eyes  of  the 
operator,  which  takes  place  generally  in  two  or  three  minutes, 
the  etching  liquid  being  kept  moving  over  the  surface  all  the 
time  by  a  camel's  hair  pencil.  As  soon  as  it  appears  proba- 
ble that  the  engraving  will  not  be  any  better,  the  operation 
is  stopped,  by  wiping  off  the  fluid  with  a  pad  of  cotton  or 
of  wool  and  afterward  flowing  the  plate  with  a  sheet  of 
cold  water.  The  plate  is  then  wiped  with  a  clean  linen 
cloth,  and  afterward  rubbed  with  soft  Spanish  white  and 
water  in  order  to  remove  the  gelatine.  The  engraving  is 
now  complete. 

Another  method  by  the  same  author  is  the  following : 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 


291 


When  the  plate  is  ready  for  etching  pour  upon  it  a  small 
quantity  of  No.  1,  the  saturated  solution.  This  may  be  left 
on  the  plate  for  a  minute  or  two.  No  apparent  effect  is  pro- 
duced by  this  operation,  but  it  acts  beneficially  by  hardening 
the  gelatine.  After  this  it  is  poured  off  and  a  sufficient 
quantity  of  No.  2  takes  its  place  and  produces  the  etching 
already  described,  which,  on  its  aj)pearing  satisfactory,  re- 
quires nothing  more  to  be  done. 

But  it  frequently  happens  that  a  few  patches  of  the  engrav- 
ing, such  as  distant  mountains  or  vessels  in  a  landscape,  re- 
fuse to  appear,  and  as  without  these  the  engraving  would 
be  incomplete,  it  is  recommended  to  apply,  by  means  of  a 
camel's  hair  pencil,  a  little  of  No.  3  to  those  parts,  without 
pouring  off  No.  2.  This  simple  means  is  frequently  effective 
in  bringing  out  the  details  of  the  picture,  and  sometimes 
with  great  rapidity,  so  that  the  operator  has  to  be  very 
cautious  lest  this  fluid  might  corrode  parts  that  are  to  re- 
main white.  With  proper  skill  this  mode  of  strengthening 
certain  parts  will  be  found  of  great  advantage  in  bringing 
out  portions  which  probably  would  remain  invisible. 

Asphaltotype  of  JVicephore  JViepce. 

The  substance  used  to  produce  the  image  on  the  plate 
under  the  influence  of  light  is  asphaltum  or  the  bitumen  of 
Judea.  The  process  of  Nicephore  Niepce  has  undergone 
various  modifications  by  his  nephew  Niepce  de  Saint  Victor. 
The  solution  of  asphaltum  was  formerly  applied  by  means 
of  a  roller  covered  with  leather,  or  of  a  pad  of  cloth  or  leath- 
er ;  it  is  now  applied  like  collodion. 

Varnish  of  Niepce  de  Saint  Victor. 

Anhydrous  benzine,  90  parts. 

Essence  of  citron-peel,  10  parts. 

Pure  bitumen  of  Judea,  2  parts. 

In  order  to  render  the  benzine  more  anhydrous,  place  a 
quantity  of  freshly  prepared  chloride  of  calcium  in  the  vial 
which  contains  it,  and  shake  the  mixture  frequently.  In 
twenty-four  hours  it  may  be  used. 

Asphaltum  or  the  bitumen  above  mentioned  dissolves  very 
easily  in  benzine ;  it  is  necessary,  however,  to  shake  the 
mixture,  and  then  to  allow  it  to  settle  for  a  day  or  two,  after 
which  the  more  liquid  part  is  decanted  and  filtered  in  order 
to  remove  all  insoluble  particles.  The  varnish  is  then  very 
fluid,  and  produces  a  very  thin  film.  The  thinner  the  film, 
the  more  sensitive  it  is  to  light.     If  a  thicker  film  bo 


292 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 


required,  it  is  obtained  by  removing  the  stopper  of  the  vial 
for  a  while,  and  allowing  the  varnish  to  evaporate,  or  by 
adding  three  or  four  parts  of  asphaltum  instead  of  two.  But  a 
thick  film  presents  more  resistance  to  the  etching  fluid,  and 
there  is  a  limit  to  its  application,  otherwise  the  half-tones  will 
be  entirely  wanting.  The  bottle  containing  the  varnish  must 
be  kept  filled  and  well  closed,  and  be  preserved  in  a  dark 
room,  if  it  is  to  be  kept  some  time.  It  is  better,  however, 
to  prepare  only  a  small  quantity  at  a  time  for  present  use. 

Preparation  of  the  Plate. 

Plates  of  steel,  copper,  zinc  or  of  glass  may  be  used  in 
this  process.  The  first  conditions,  naturally,  for  all  such 
operations  of  contact-printing,  are,  that  they  be  perfectly 
plane  and  well-polished.  Whether  direct  from  the  planing- 
machine  or  from  previous  use  where  it  has  failed  to  succeed, 
the  plate  of  steel,  for  instance,  is  cleaned  with  benzine  in 
order  to  remove  all  greasy  material,  then  rubbed  with  a  pad 
of  cotton  dipped  in  alcohol  ninety-five  per  cent  strong,  and 
very  fine  emery  powder.  By  this  means  the  steel  can  be 
polished  as  bright  as  a  daguerreotype  plate.  Copper  and  zinc 
plates  as  also  those  of  glass  are  polished  with  rotten-stone, 
Immediately  before  use  it  is  well  to  cover  the  steel,  etc.,  plate, 
with  a  coating  of  rotten-stone  and  alcohol,  allow  the  film  to  dry 
and  then  to  rub  it  off ;  afterward  use  the  broad  camel's  hair 
pencil,  as  in  the  wet  collodion  process,  in  order  to  remove 
all  particles  of  dust. 

Flowing  of  the  'Varnish. 

This  operation  is  similar  to  many  others  already  briefly 
described.  Be  careful  not  to  shake  the  varnish  before  it  is 
poured  upon  the  plate,  otherwise  it  will  give  rise  to  an  in- 
finite number  of  small  bubbles  in  the  film.  Pour  the  varnish 
either  on  the  middle  or  the  upper  right-hand  corner  of  the 
plate,  as  you  would  collodion,  and  as  you  are  accustomed  to 
do  so  with  success ;  and  allow  the  excess  to  flow  off  at  the 
lower  right-hand  corner.  Invert  the  plate  and  let  it  lean 
against  the  wall  on  the  opposite  corner  to  that  from  which 
the  excess  was  poured  and  with  the  fiim  toward  the  wall. 
This  operation  may  be  performed  in  a  weak  diffused  light ; 
let  the  plate,  however,  dry  in  the  dark-room,  which  will 
take  place  very  rapidly,  and  use  it  as  soon  as  dry ;  for  its 
sensibility  is  now  the  greatest.  The  more  uniform  and  thin 
(to  a  certain  extent)  the  film  may  be,  the  greater  the  proba- 
bility of  a  successful  issue. 


PRINTING  WITHOUT  THE  SALTS  OF  SILVEE.  293 


Exposure  of  the  Plate. 
The  printing  operation  is  performed  in  the  printing  frame, 
only  a  transparent  positive  is  used  instead  of  a  negative.  A 
paper  print  maybe  substituted  for  the  glass  positive,  first  mak- 
ing the  paper  transparent  by  a  solution  of  wax  in  turpentine 
or  otherwise.  The  glass  positive  is  placed  upon  the  glass 
plate  of  the  printing  frame  ;  and  then  the  prepared  asphal- 
tum  plate  lies  upon  the  positive,  their  two  films  being  in 
contact.  In  this  the  frame  is  exposed  to  the  direct  rays  of 
the  sun  or  to  diffused  light.  The  time  of  exposure  will  sel- 
dom exceed  a  quarter  of  an  hour  in  the  sun  or  an  hour  in 
diffused  light ;  the  right  time  has  to  be  learned  by  experience. 

Development  of  the  Image. 
This  operation  consists  in  dissolving  the  parts  that  have 
not  been  acted  upon  by  light  and  thus  removing  them  and 
exposing  the  plate  beneath. 

Solvent. 

Rectified  oil  of  naphtha,  4  parts. 

Ordinary  benzine,  1  part. 

This  solvent  is  poured  upon  small  plates  in  the  same  way 
as  collodion,  or  the  developer,  etc. ;  but  when  the  plates  are 
large,  it  is  necessary  to  have  a  porcelain  or  glass  dish,  at  the 
bottom  and  the  left  end  of  which  the  plate  is  placed.  The 
solvent  is  poured  upon  the  inclined  right  end,  and  by 
elevating  this  end  the  liquid  flows  uniformly  over  the  whole 
plate.  This  operation  of  flowing  the  plate  must  be  perform- 
ed immediately  after  the  exposure,  whether  in  the  camera 
or  by  contact. 

If  the  action  of  the  light  has  been  too  long,  a  stronger 
solvent  is  needed  ;  the  strength  of  this  solution  is  increased 
either  by  increasing  the  quantity  of  the  benzine  or  diminish- 
ing that  of  the  naphtha.  If  the  whole  of  the  film  of  asphal- 
tum  is  dissolved  off,  the  action  of  the  light  has  not  been 
either  sufficiently  intense  or  prolonged  ;  if,  on  the  contrary, 
but  little  has  been  dissolved,  either  the  luminous  action  has 
been  too  long,  or  the  asphaltum  was  very  sensitive,  in  which 
case  the  image  is  always  foggy. 

If  the  asphaltum  peels  off  in  certain  parts  of  the  plate,  it 
is  an  evident  sign  the  plate  was  moist.  It  sometimes  happens, 
however,  that  when  the  film  is  too  thick,  the  same  incon- 
venience takes  place. 

The  solvent  may  be  used  several  times  in  succession, 
taking  care  to  filter  it  when  it  becomes  too  colored. 


294 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 


Washing  of  the  Plate. 
The  picture  in  general  appears  very  quickly,  so  that  the 
action  of  the  solvent  has  to  be  stopped  almost  immediately 
after  its  application.  If  the  exposure  has  been  too  long, 
the  solvent  action  of  the  varnish  is  not  so  rapid.  In  order 
to  prevent  all  further  action,  the  plate  is  plunged  into  a 
vessel  of  water  and  afterward  well  washed  beneath  the  tap 
until  every  trace  of  the  solvent  and  all  particles  of  dust  are 
removed.  The  plate  is  then  allowed  to  dry  spontaneously, 
or  is  dried  by  artificial  heat. 

Fumigation  of  the  Plates. 
The  film  of  asphaltum,  unfortunately,  is  not  quite  imper- 
meable to  the  action  of  the  etching  fluid  used  afterward. 
Various  means  have  been  resorted  to  so  as  to  obviate  this 
difficulty.  Wax  is  sometimes  added  in  small  proportions 
to  the  varnish  to  remedy  this  evil.  The  best  result  is  ob- 
tained by  subjecting  the  plates  after  development  to  the 
vapors  of  the  essence  of  lavender  or  spikenard.  For  this 
purpose  an  arrangement  is  required  similar  to  those  used 
for  iodizing  the  silver  plate  in  the  daguerreotype  process. 
At  the  bottom  of  this  vessel  a  small  porcelain  capsule  is 
placed  containing  the  pure  essential  oil  not  distilled  or  rec- 
tified, which  is  heated  from  below  by  means  of  a  spirit-lamp 
to  the  temperature  of  about  from  150°  Fahrenheit  to  170°  at 
the  most,  lest  the  oil  should  be  volatilized  in  too  large  a  quan- 
tity. In  the  first  place  let  the  fumigator  be  filled  with  vapor, 
then  introduce  the  plate  and  keep  it  there  for  two  or  three 
minutes.  The  same  essence  may  be  used  a  second  timeN 
but  no  more. 

The  color  of  the  film  after  fumigation,  when  successful, 
must  be  the  same  as  before  it  has  been  acted  upon  by  the 
light,  bronzed  and  iridescent. 

The  plate  is  then  dried  by  exposing  it  a  moment  to  the 
air  before  the  etching  fluid  is  applied,  and  if  the  operation 
of  fumigation  has  been  properly  timed  and  conducted,  the 
film  has  become  quite  impermeable.  It  is  necessary  to 
guard  against  carrying  the  deposition  of  the  essential  oil 
too  far,  otherwise  the  acids  will  have  no  action  whatever 
upon  the  metallic  plate. 

Application  of  the  Aqua-Tinta  Granulation. 
This  operation  is  indispensable  for  plates  obtained  direct 
either  by  contact  or  in  the  camera  from  a  photograph,  a 
landscape  or  portrait,  etc. ;  if  the  plate  be  copied  from  an 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER.  295 

engraving,  it  is  not  necessary.  Without  this  expedient  the 
plate  will  not  retain  the  ink. 

The  grain  is  applied  in  the  following  manner :  Resin  re- 
duced to  an  impalpable  powder  is  placed  at  the  bottom  of 
a  box  made  for  this  purpose,  which,  by  means  of  a  pair  of 
bellows,  is  raised  into  a  cloud,  and  thus,  when  it  settles  on 
the  plate,  communicates  to  the  latter  the  granular  condi- 
tion denominated  aqua-tinta.  The  plate  is  then  heated, 
whereby  the  resin  becomes  melted  and  forms  a  sort  of  net- 
work over  the  whole  surface.  This  operation  gives  the 
shades  a  grain  more  or  less  fine,  (according  to  the  impal- 
pability of  the  powder,)  which  retains  the  printing  ink,  and 
thus  permits  numerous  impressions  to  be  taken  of  the  plate 
as  soon  as  the  varnish  and  the  resin  have  been  removed  by 
the  aid  of  fatty  bodies  and  essential  oils  or  benzine. 

Etching  of  the  Plate, 

It  would  be  useless  to  attempt  to  etch  a  plate  where  the 
conditions  are  not  appropriate.  The  film  must  have  a  bril- 
liant and  iridescent  appearance,  be  sufficiently  imperme- 
able to  the  acid  employed,  free  from  fogginess,  (that  is,  the 
metallic  plate  must  be  completely  denuded  in  the  deep 
shadows  and  partially  so  in  the  half-tones,)  and  the  aqua- 
tinta  grain  must  have  been  communicated  to  it.  This  being 
the  case,  proceed  as  follows  : 

Raise  a  border  of  mastic  all  round  the  edge  of  the  plate, 
and  varnish  those  parts  that  are  intended  to  be  quite  white 
in  the  print,  as  is  practised  in  ordinary  etching.  Next  pour 
upon  the  film  a  dilute  solution  of  nitric  acid,  beginning  with 
one  per  cent  of  acid,  and  strengthening  it  to  as  high  as 
twelve  per  cent,  according  to  the  resistance  of  the  varnish 
and  the  depth  of  etching  required.  The  etching  fluid  has 
to  be  changed,  without  increasing  the  per  centage  of  acid ; 
for  it  frequently  happens  that  the  plate  resists  the  action 
of  the  fluid  for  some  time,  and  especially  if  the  film  has 
been  fumigated  with  the  essential  oil  of  spikenard.  Very 
good  results  may  be  obtained  by  pouring  hot  water  over 
the  plate  before  the  acid  is  applied  ;  but  in  this  case  be  sure 
to  remove  every  bubble  of  water  from  the  interstices  by 
blowing  before  you  pour  on  the  etching  fluid. 

As  soon  as  the  etching  is  supposed  to  have  advanced  far 
enough,  all  further  action  is  suppressed  by  dipping  the  plate 
in  cold  water ;  this  must  be  done  in  time,  otherwise  the 
varnish  would  be  attacked  in  those  parts  that  ought  to  be 
preserved,  a  circumstance  that  sometimes  happens,  for  which 


296 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 


unfortunately  no  definite  cause  can  be  ascribed.  To  obviate 
this  difficulty  a  saturated  solution  of  iodine  in  water  at  6CT 
is  used  as  an  etching  fluid,  instead  of  the  aqua-fortis.  The 
fumigation  is  omitted ;  and  the  iodine  solution  is  poured 
upon  the  plate  and  kept  there  for  ten  or  fifteen  minutes,  until 
it  becomes  nearly  colorless ;  this  operation  is  repeated  two 
or  three  times,  until  the  etching  is  regarded  as  deep  enough 
or  nearly  so ;  it  is  then  terminated  by  employing  a  dilute  so- 
lution of  aqua-fortis,  which  completes  the  etching  without 
attacking  the  varnish. 

Copper  requires  a  much  stronger  etching  fluid  than  either 
steel  or  zinc,  and  iodine  can  not  be  used  in  this  case  ;  it  has 
therefore  been  recommended  to  etch  the  parts  by  galvanism. 

The  plates  in  general  require  touching  up  with  the  graver, 
especially  if  copied  from  photographs ;  whereas  distinct  pen 
and  ink  drawings  or  plans  or  maps  may  be  engraved  in  the 
way  prescribed,  without  requiring  the  aid  of  the  graver's 
tool. 

Etching  on  Glass. 
Etching  on  glass  is  performed,  when  the  plates  are  pre- 
pared, by  placing  them  with  the  film  downward  over  the 
fumes  of  hydrofluoric  acid.  For  this  purpose  a  box  is  con- 
structed of  lead,  of  the  size  and  shape  of  the  plate,  and 
about  two  inches  deep.  At  the  bottom  of  this  place  a  small 
saucer  of  lead  containing  pulverized  fluor  spar  and  sulphuric 
acid  intimately  mixed.  Cover  the  box  with  the  inverted  and 
prepared  plate  as  a  lid,  and  apply  heat  to  the  bottom  of  the 
leaden  box  by  means  of  a  spirit-lamp  ;  fumes  of  hydrofluoric 
acid  will  be  set  at  liberty,  and  will  corrode  those  parts  of  the 
glass  that  have  been  denuded  by  the  solvent. 

Negress  Process  for  Heliographic  Engraving. 
The  plate,  prepared  either  with  asphaltum  or  the  bichro- 
mate of  potassa  and  gelatine,  is  subjected  to  the  luminous 
impression  beneath  a  positive  instead  of  a  negative.  After 
exposure  and  washing,  the  plate  is  attached  to  the  negative 
pole  of  a  battery  and  immersed  in  a  solution  of  gold  for 
electrolytic  purposes.  In  this  way  the  lights  of  the  design 
are  protected  with  a  film  of  gold,  the  middle  tones  are  par- 
tially covered,  and  the  blacks  only  just  sufficient  to  commu- 
nicate a  sort  of  reticulated  structure  which  forms  the  ne- 
cessary grain. 

Copies  for  the  Engraver  to  work  from. 
The  metallic  plate,  the  wood,  stone  or  glass  is  first  covered 
on  both  sides  with  a  varnish  quite  impermeable  to  the  action 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 


297 


of  acids;  it  is  then  flowed  on  the  prepared  surface  with 
iodized  or  bromo-iodized  collodion,  and  treated  in  every  re- 
spect the  same  as  a  glass  plate  for  the  reception  of  an  ambro- 
type ;  that  is,  it  is  sensitized  in  the  bath  of  nitrate  of  silver, 
exposed  in  the  camera,  or  by  contact  with  an  albumen,  etc., 
print  on  glass  to  the  view,  etc.,  developed,  fixed,  washed 
and  dried.  Finally,  the  surface  of  the  picture,  thus  obtain- 
ed, is  covered  with  a  solution  of  dextrine  to  preserve  it  from 
injury.  The  plate,  etc.,  is  now  ready  for  the  draughtsman, 
and  when  prepared  by  him  by  means  of  a  fine-pointed  style, 
it  is  submitted  to  the  etching  fluid,  as  before  directed. 

Photo-lithography  and  Photo-zincography. 

These  branches  have  been  brought  to  a  high  degree  of 
success  within  the  last  two  or  three  years.  They  are  not 
yet  quite  perfect ;  the  want  of  perfection  consists  in  the  in- 
ability to  obtain  easily  and  uniformly  the  middle  tones.  Draw- 
ings in  pen  and  ink,  maps,  plans,  pages  of  letter  press,  etc., 
in  which  there  is  no  intermediate  tones  between  the  lights 
and  shades,  are  executed  to  any  amount  of  reduplication  by 
the  photo-lithographic  process,  and  very  successfully ;  but 
landscape  scenery,  architecture  and  portraiture,  where  there 
is  a  regular  blending  of  light  into  shade,  can  not  always  and 
at  will  be  reproduced  satisfactorily  by  any  of  the  known 
processes  of  photo-lithography  or  photo-zincography,  al- 
though it  must  be  confessed  that  the  specimens  published  in 
the  work  on  Photo-zincography  by  Colonel  Sir  Henry  James 
indisputably  prove  the  possibility  of  the  accomplishment  of 
this  desideratum. 

The  various  processes  practised  in  this  department  of  pho- 
tography depend  upon  the  properties  of  asphaltum,  the  per- 
salts  of  iron,  and  of  chrome  already  frequently  alluded  to  ; 
and  the  object  to  be  attained  consists  either  in  preparing 
surfaces  where  the  shades  are  etched  out  as  in  the  copper- 
plate, or  in  relief,  as  in  common  type. 

In  some  processes  the  designs  are  taken  directly  upon 
stone  or  zinc;  in  others  on  prepared  paper,  and  afterward 
transferred  to  stone  or  zinc.  By  the  latter  the  picture  is  ob- 
tained in  a  direct  position  ;  whereas  by  the  former,  without 
previous  arrangement,  the  image  is  inverted. 

Asphalto-photolithographic  Process. 
This  process  was  originally  employed  by  Nicephore  Niepce 
in  the  production  of  heliographic  engravings.    The  first  at- 
tempts in  photolithography  were  made  at  the  suggestion  of 


298  PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 


Barresvvil,  in  connection  with  Lernercier,  a  lithographer,  and 
Lerebours,  an  optician.  Davanne,  too,  co-editor  with  Bar- 
reswil,  of  the  Chimie  Photographiqae^  assisted  in  the  pre- 
paration of  the  specimens  published  as  early  as  1853. 

The  properties  of  asphaltnm  dissolved  in  ether  or  in  es- 
sential oil,  are  the  following  : 

First.  It  is  sensitive  to  light,  and  becomes  changed  in  pro- 
portion to  the  intensity,  whereby  parts,  not  acted  upon  by 
the  luminous  impression,  can  be  removed  by  a  subsequent 
operation  of  washing  with  a  solvent. 

Second.  It  is  sufficiently  adhesive  to  the  stone  and  im- 
permeable to  the  etching  liquids  to  prevent  the  latter  from 
acting  upon  the  stone,  excepting  on  the  parts  denuded  by  the 
solvent. 

Third.  The  parts  of  asphaltum  left  on  the  stone  have  an 
attraction  for  the  greasy  ink  used  in  photo-lithography. 

Now  these  are  the  properties  required  in  photo-litho- 
graphy: 

The  stone  is  first  prepared  as  for  lithographic  purposes,  and 
then  placed  on  a  leveling  stand  and  made  perfectly  hori- 
zontal. Next  take  a  quantity  of  bitumen,  reduce  it  to  a 
powder  and  dissolve  it  in  ether ;  filter  as  much  of  the  solu- 
tion as  may  be  required  to  flow  the  stone.  Whilst  flowing 
the  stone  with  this  preparation  be  very  careful  to  avoid  agi- 
tating the  air  so  as  to  set  the  dust  in  motion,  or  produce  un- 
dulations in  the  film.  The  excess  of  bitumen  may  be  allowed 
to  flow  off  on  the  sides  and  corners ;  and  where  there  is  a 
tendency  of  the  fluid  to  become  stagnant  or  to  flow  back 
again  rvpon  the  stone,  this  is  prevented  by  the  application  of 
a  glass  rod  to  guide  the  superfluous  fluid  over  the  sides. 
The  object  is  to  obtain  a  thin,  uniform  film,  which  beneath  a 
magnifying  glass  presents  a  reticulated  appearance  all  over 
the  stone,  communicating  to  it  what  is  denominated  by  en- 
gravers a  grain.  The  quantity  of  asphaltum  in  ether  re- 
quired to  produce  such  a  thin  and  uniform  film  has  to  be 
ascertained  by  practice. 

As  soon  as  the  asphaltum  is  dry,  a  negative  is  placed  on  its 
surface,  (the  two  films  being  in  juxtaposition,)  and  is  held 
down  in  contact  by  pressure  on  the  sides  and  corners  by  means 
of  a  pressure-frame.  Any  negative  may  be  used.  The  stone 
is  now  exposed  to  the  light  of  the  sun  for  a  time,  which  has 
to  be  learned  by  experience.  This  operation  being  con- 
cluded, the  stone  is  taken  into  a  room  feebly  lighted,  the 
negative  is  removed  and  the  surface  containing  the  latent 
image  is  washed  with  ether.    The  parts,  on  which  the  light 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 


299 


lias  acted,  have  become  insoluble  /  these,  therefore,  are  not 
disturbed  by  the  solvent ;  whereas  all  the  rest  of  the  bitu- 
minous film  that  has  been  protected  by  the  shades  of  the 
negative,  is  dissolved  and  washed  off.  If  the  time  of  expo- 
sure has  been  too  short,  the  image  is  destitute  of  all  middle 
tones  ;  it  is  mere  black  and  white ;  if,  on  the  contrary,  the 
exposure  has  been  too  long,  the  picture  is  foggy,  that  is,  the 
fine  lines  have  become  heavy  and  the  stone  imperfectly  de- 
nuded in  the  lights.  In  order  to  be  successful,  the  surface 
must  be  well  washed  with  ether,  otherwise  spots  will  arise 
that  can  not  afterward  be  removed. 

The  film  is  then  dried,  and  if  the  image  thus  formed  is  satis- 
factory, the  stone  is  then  treated  in  the  same  manner  as  a 
drawing  with  lithographic  crayons  ;  that  is,  it  is  first  flowed 
with  a  weak  acid  solution  containing  a  little  gum,  so  as  to 
preserve  the  whites  and  give  more  transparency  to  the  pic- 
ture ;  it  is  then  washed  in  several  waters,  and  if  need  be,  in  oil 
of  turpentine  ;  finally  it  is  inked  with  lithographic  ink.  If  all 
succeeds  well,  the  image  will  take  the  ink  with  facility  as  soon 
as  the  roller  is  passed  over  it,  and  will  require  no  touching 
up.  Prints  are  obtained  from  stones,  prepared  in  the  man- 
ner above  described,  as  with  any  other  lithographic  stone ; 
they  improve  gradually  after  a  number  of  impressions  have 
been  taken.  The  authors,  whose  process  I  have  copied,  as- 
sert that  they  have  prepared  a  number  of  stones  by  this  pro- 
cess, that  have  given  great  satisfaction  and  have  not  been 
worn  out  quicker  than  any  ordinary  lithographic  impression. 

Bicliromo-plioto-litlxogvaphic  Processes  of  Poitemn. 

The  mixture  proposed  by  Talbot  of  bichromate  of  potassa 
and  organic  matter,  such  as  gelatine,  albumen,  gum,  etc.,  is 
used  by  Poitevin  in  the  processes  about  to  be  described. 

An  ordinary  lithographic  stone  is  covered  with  a  solution 
of  albumen  and  bichromate  of  potassa,  and  allowed  to  dry 
spontaneously.  It  is  then  exposed  to  the  light  of  the  sun 
beneath  an  albumen,  tannin,  etc.,  negative,  by  which  the  parts 
to  which  the  light  has  not  been  able  to  penetrate  through  the 
opaque  shades  of  the  negative,  are  preserved  in  their  natural 
and  soluble  condition,  while  the  parts  impressed  by  the  light 
have  become  insoluble.  Thus  modified,  the  latter  parts  repel 
water,  as  if  the  light  had  produced  some  greasy  substance 
in  the  film.  In  this  condition  these  parts  easily  adhere  to 
ordinary  lithograpic  ink,  whilst  there  is  no  adherence  be- 
tween the  ink  and  those  parts  that  have  undergone  no  actinic 
impression.    A  roller  charged  with  such  ink  is  then  passed 


300  PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 

over  the  stone ;  and  the  image  is  made  manifest  by  the  ad- 
herence of  the  ink  to  the  parts  impressed  and  in  accordance 
with  the  intensity  of  the  impression.  The  excess  of  ink  is 
removed  with  a  wet  sponge.  The  stone  is  then  covered  with 
a  weak  acid  which  acts  upon  the  parts  not  imbued  with  ink, 
and  thus  presents  the  image  in  relief,  which  is  treated  after- 
ward like  any  other  ordinary  drawing  on  stone  with  litho- 
graphic crayons. 

Photo-typographic  Process  of  Poitevin. 
Poitevin  has  also  availed  himself  of  a  peculiarity,  which 
gelatine  in  connection  with  bichromate  of  potassa  possesses, 
of  swelling  when  exposed  to  cold  water  and  before  it  has 
been  impressed  by  light.  His  mode  of  proceeding  is  as 
follows  : 

A  plate  of  glass  is  flowed  with  an  even  film  of  a  solution 
of  gelatine,  which  is  allowed  to  dry  spontaneously.  The 
plate  is  then  immersed  in  a  concentrated  solution  of  bichro- 
mate of  potassa  ;  and  when  the  film  has  become  completely 
permeated  with  the  salt,  the  plate  is  quickly  washed  in  order 
to  remove  all  excess  of  the  solution,  and  is  put  away  in  the 
dark-room  to  dry.  The  plate  is  then  ready  for  exposure 
beneath  a  negative,  which  must  be  very  clear,  transpar- 
ent, well-defined  and  vigorous.  After  exposure  it  is  im- 
mersed in  cold  water,  by  which  the  parts  that  have  been 
protected  beneath  the  dark  shades  of  the  negative,  swell.  In 
this  condition  the  plate  is  moulded  in  plaster.  This  mould 
is  afterward  submitted  to  the  electrolytic  action  of  a  gal- 
vanic battery,  from  which  a  metallic  matrix  may  be  obtained 
for  printing  from  by  the  typographic  press. 

The  processes  above  described,  whatever  the  success  in 
manipulation,  are  defective  in  one  essential  point:  the  pic- 
tures are  laterally  inverted.  It  is  true  that  negatives  may 
be  obtained  by  copying  in  a  condition  to  produce  the  proper 
effect. 

Photo-lithographic  Process  of  Newton. 

A  lithographic  stone  or  a  plate  is  covered  with  a  solution 
of  one  quart  of  water,  four  ounces  of  gum-arabic,  one  hun- 
dred and  sixty  grains  of  sugar,  and  a  certain  quantity  of  bi- 
chromate of  potassa.  The  stone  is  then  put  away  to  dry  in 
the  dark-room.  It  is  next  exposed  either  in  the  camera  or 
beneath  a  transparent  positive.  The  gum  becomes  almost 
insoluble  by  the  action  of  the  light.  The  stone  is  then  washed 
with  a  solution  of  soap,  which  removes  the  parts  that  have 
not  been  acted  upon  by  light,  while  the  soap  is  decomposed 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER.  301 


in  those  parts  where  the  luminous  impression  has  been  made, 
"the  action  of  the  soap  being  inversely  proportional  to  the 
intensity  of  the  light."  The  stone  thus  prepared  is  washed 
with  water,  and  when  it  is  dry  it  is  covered  by  means  of  a 
roller  with  a  layer  of  printer's  ink,  which,  combining  with 
the  soap,  adds  new  body  to  the  print.  When  it  is  desired 
to  obtain  gradations  of  light  and  shade,  the  stone  is  submitted 
to  the  graining  process  above  described;  but  this  is  not  ne- 
cessary where  blacks  and  whites  alone  are  required. 

It  is  difficult  to  observe  any  fundamental  difference  be- 
tween this  process  of  Newton  and  the  preceding  one  of  Poi- 
*tevin ;  it  is  apparently  a  mere  copy.  The  remaining  pro- 
cesses to  be  described  are  the  most  important  and  successful ; 
they  are  founded  upon  a  discovery  of  Asser  of  Amsterdam, 
the  transfer-process,  although  Sutton  had  remarked  that 
printer's  ink,  put  on  gelatine  paper,  would  come  away,  if 
soaked  in  water,  leaving  the  paper  quite  clean. 

This  process  consists  in  first  obtaining  a  picture  on  paper 
prepared  with  bichromate  of  potassa  and  organic  matter, 
and  then  in  transferring  this  direct  picture  on  stone  or  zinc, 
which,  being  laterally  inverted,  yields  a  direct  print  in  the 
press.  The  process  has  been  much  improved  in  the  manipu- 
lations both  by  Osborne  in  Australia,  as  well  as  by  Captain 
Scott  and  Colonel  Sir  Henry  James,  in  the  Ordnance  Office, 
Southampton.  Osborne,  it  appears,  made  his  discoveries  and 
improvements  independently  of  Asser's  publication,  and  of 
those  from  the  Government  office  in  Southampton.  These 
processes  being  then  essentially  the  same,  it  will  not  be  ne- 
cessary to  describe  more  than  one  in  this  work.  Colonel  Sir 
H.  James  has  just  published  a  new  edition  of  his  Photo-zin- 
cography, accompanied  with  very  neat  specimens  of  prints 
that  can  be  obtained  directly  from  photographic  negatives 
by  this  process. 

Photo-zincography  by  Colonel  Sir  H.  James,  P.JE.  /  and 
Photo-lithography  by  Mr.  Osborne. 
The  negatives  in  this  sort  of  work  require  above  all  things 
to  be  very  transparent,  without  the  slightest  fogginess  in 
the  transparent  parts ;  the  opaque  j3arts,  on  the  contrary, 
must  be  exceedingly  dense.  Such  negatives  can  be  obtained 
only  by  redevelopment  or  intensifying.  The  exposure  of 
the  collodion  plate  to  light  is  not  quite  so  long  as  for  an 
ordinary  negative,  nor  is  the  development  carried  on  to  the 
same  extent  in  the  first  instance  as  for  a  negative ;  it  is  bet- 
ter to  stop  the  action  of  the  iron  solution  as  soon  as  the  pic- 


302 


PKINTING  WITHOUT  THE  SALTS  OF  SILVER. 


ture  has  appeared  in  full  brilliancy  as  a  positive,  and  then  to 
intensify  afterward.  For  copying  engravings,  pen  and  ink 
drawings,  maps,  plans,  etc.,  where  the  delineations  are  purely 
black  and  white,  this  mode  of  preparing  the  negatives  is  cer- 
tainly to  be  recommended.  Where  there  is  a  gradation  of 
tone,  the  time  of  exposure  and  of  development  must  be  in- 
creased beyond  that  of  a  positive  or  ambrotype,  but  yet  not 
to  the  same  extent  as  for  a  negative. 

To  intensify  the  first  sort  of  negative,  that  is,  the  one  for 
copying  engravings,  etc.,  proceed  as  follows,  as  soon  as  it  has 
been  developed  and  fixed  and  is  perfectly  clear  in  the  trans- 
parent parts : 

While  the  plate  is  still  moist,  flow  it  with  a  part  of  the 
following  solution : 

Pyrogallic  acid,  *        ...    3  grains. 


After  moving  the  solution  backward  and  forward  for  a 
minute  or  so,  pour  it  off  into  a  wine-glass,  and  add  to  it 
about  six  drops  of  a  solution  of  nitrate  of  silver  thirty  per 
cent  strong,  if  the  plate  is  stereoscopic  size,  and  so  on,  ac- 
cording to  the  size ;  shake  the  mixture  well  and  then  flow 
the  plate  with  it,  and  keep  it  in  motion,  and  watch  the  prog- 
ress of  blackening  by  the  light  transmitted  from  below,  as 
before  directed  and  described  in  the  article  on  the  negative 
collodion  plate.  It  may  be  necessary  to  add  more  silver,  or 
even  to  repeat  the  dose  of  the  intensifier,  sometimes  two  or 
three  times ;  this,  however,  is  a  rare  occurrence  if  the  time 
of  exposure  has  been  right.  When  the  shades  are  quite 
opaque,  the  operation  is  so  far  complete.  Wash  thoroughly 
and  examine  the  plate  in  diffused  light.  If  the  lines  have 
become  somewhat  thickened,  or  the  transparent  parts  slightly 
fogged,  these  evils  must  be  remedied  by  Osborne's  clarify- 
ing process. 

Dissolve  iodine  in  a  solution  of  iodide  of  potassium  to 
saturation  ;  of  this  solution  take  ten  or  twelve  drops  to  four 
drachms  of  water,  (for  a  stereoscopic  plate,)  and  pour  the  so- 
lution on  the  moist  plate,  and  keep  it  in  motion  until  ihe  sur- 
face of  the  negative  assumes  a  uniform  film  of  a  cream  color. 
Wash  the  plate  and  flow  it  with  a  very  dilute  solution  of 
cyanide  of  potassium.  This  will  remove  the  iodide  of  silver 
and  diminish  the  thickness  of  the  lines  and  the  fogged  ap- 
pearance of  the  transparent  parts. 

Sir  H.  James  intensifies  with  bichloride  of  mercury,  by 


Glacial  acetic  acid, 
Alcohol,    .    .  . 
Distilled  water,  . 


48  minims. 
36  minims. 
2  ounces. 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER.  303 


immersing  the  well- washed  plate  in  a  weak  solution  of  this 
salt ;  as  soon  as  the  surface  is  whitened  by  the  action  of 
the  mercurial  salt,  it  is  washed  again,  and  a  dilute  solution 
of  sulphide  of  ammonium  is  poured  over  it,  which  changes 
the  color  to  a  brown-yellow.  If  the  negative  is  allowed  to 
dry,  the  bichloride  is  used,  there  will  be  less  danger  of  fill- 
ing up  the  lines  ;  but  the  edges  of  the  film  must  be  varnished 
first,  to  prevent  it  from  slipping  off  when  it  is  washed. 

After  the  negative  has  been  intensified  and  is  dry,  it  is 
varnished,  and  is  then  ready  for  use. 

The  following  are  the  formulae  for  the  various  solutions 
recommended  by  Sir  H.  James  : 

For  Cleaning  the  Glass  Plate. 

Alcohol,  1  ounce. 

Ammonia,  J  drachm. 

Water,  8  ounces. 

Tripoli  powder,  sufficient  to  give  it  the  consistence  of  cream. 

Collodion. 

Pyroxyline,  80  grains. 

Iodide  of  cadmium,  15  grains. 

Iodide  of  potassium,  75  grains. 

Alcohol,  sp.  gr.,  .812,  10  ounces. 

Ether,  sp.  gr.,  .725,  10  ounces. 

Nitrate  of  Silver  Bath. 

Nitrate  of  silver  recrystallized  or  fused,  .    .    1  ounce. 
Water,  14  ounces. 

Dissolve  and  filter,  then  coat  a  plate  with  iodized  collo- 
dion, and  immerse  for  twelve  hours  in  order  to  saturate  the 
bath  with  iodide.  If,  on  exposing  the  plate,  there  should  be 
any  sign  of  fogging,  add  dilute  nitric  acid,  (one  of  acid  to 
ten  of  water,)  drop  by  drop,  until  a  clear  picture  is  obtain- 
ed. If  at  any  time  the  bath  should  be  too  acid,  it  can  be 
neutralized  by  adding  a  little  oxide  of  silver. 

Developing  Solutions. 


Iron. 

Protosulphate  of  iron,  .    1  ounce. 
Glacial  acetic  acid,    .    .    6  drachms. 

Alcohol,  6  drachms. 

"Water,  distilled,  .    .    .20  ounces. 


Pyrogallic  Acid. 
Pyrogallic  acid,  ,    .    .    30  grains. 
Glacial  acetic  acid,    .    .    1  ounce. 

Alcohol,  6  drachms 

Water,  distilled,     .    .    20  ounces. 


Fixing  Solution. 

Cyanide  of  potassium,  15  grains. 

Water,  1  ounce. 


304 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 


Quality  of  the  Paper  used  in  the  Transfer  Process. 

The  paper  suitable  for  this  purpose  must  be  hard,  thin, 
and  tough,  of  even  texture,  free  from  wooliness,  and  but 
slightly  sized.  Paper  made  from  linen  is  the  best,  such  a^ 
that  used  for  bank  post  paper.  If  there  is  too  much  size  in 
the  structure,  it  can  be  remedied  by  steeping  the  paper  in 
hot  water  a  short  time  before  coating  it  with  the  solution. 

Coating  of  the  Paper  with  the  Sensitive  Solution. 
This  solution  must  be  quite  fluid  at  the  temperature  of  100°. 

Dissolve  |  bichromate  of  potassa  .    .  jounces.? 

(  Hot  water,  ram  or  distilled,)    ...    10   ounces.  ) 

Dissolve  j  £eltat:nte>  (*e  .finest,)  3  ounces.  )  N 

(  Hot  water,  (rain,  etc.,)  40   ounces.  J 

Mix  the  two  solutions  and  filter  while  warm.  When  about 
to  be  used  let  it  be  poured  into  a  large  flat  dish,  and  main- 
tained at  a  temperature  of  100°  by  placing  this  dish  in  an- 
other containing  warm  water. 

Float  the  paper  on  this  solution  with  the  right  side  down- 
ward for  three  minutes,  taking  care  to  break  up  all  bubbles ; 
the  ojDeration  is  performed  in  the  dark-room.  Drain  the 
paper  and  hang  it  up  to  dry  in  the  manner  already  described 
in  the  positive  printing  process.  When  dry,  the  paper  is 
floated  a  second  time  and  hung  up  to  dry  by  an  opposite 
corner. 

The  surface  is  afterward  smoothed  by  passing  it  through 
a  copperplate  press  on  a  hot  steel  plate — the  rolling  press 
with  a  flat  plate  is  also  quite  suitable  for  this  purpose. 

Exposure  under  the  Negative. 
The  amount  of  exposure  is  regulated  by  the  appearance 
of  the  print.  When  the  lines  appear  distinctly  marked,  and 
of  a  dark  brownish-green,  the  operation  is  complete.  The 
time  will  vary  with  each  negative,  and  with  the  light,  from 
one  minute  in  the  sun  to  twenty  minutes  in  dull  weather.  If 
the  printing  is  incomplete,  the  lines  will  break  beneath  the 
sponge  in  the  washing ;  and  where  the  exposure  has  been 
too  long,  the  ink  (to  be  afterward  applied)  will  adhere  to  the 
ground  of  the  print. 

The  Inlcing  of  the  Bichromate  Print. 
For  inula  for  the  Info 

Chalk  lithographic  ink,  2  pounds. 

Middle  linseed  oil  varnish,  1  pound. 

Burgundy  pitch,  4  ounces. 

Palm  oil,  2  ounces. 

White  wax,   2  ounces. 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER. 


305 


Melt  the  three  latter  in  an  iron  pot  until  they  begin  to 
burn,  stirring  the  ingredients  all  the  time ;  finally,  add  the 
varnish  and  the  ink,  and  mix  intimately. 

When  about  to  use  this  ink,  the  necessary  quantity  is 
melted  with  a  proportion  of  turpentine,  so  as  to  reduce  it, 
when  cold,  to  the  consistence  of  thick  molasses.  A  small 
quantity  is  laid  on  the  printing  roller,  which  is  then  worked 
on  a  stone  in  the  usual  manner,  till  the  coating  is  perfectly 
even. 

The  closer  and  finer  the  lines  of  the  print  are,  the  thinner 
should  be  the  coating  of  ink. 

A  zinc  plate  is  inked,  with  the  printing  roller,  and  the  bi- 
chromate print  is  laid  face  downward  on  it,  and  passed 
through  a  lithographic  press ;  by  this  means  it  receives  a 
very  even  coating  of  ink. 

The  Cleaning  of  the  Surface  of  the  Print, 
After  the  operation  of  inking  the  print  is  floated  on  water 
at  90°,  back  downward,  for  five  minutes  ;  it  is  then  placed 
face  upward  on  a  porcelain  or  marble  slab,  and  the  surface 
is  gently  rubbed  with  a  new  soft  sponge  dipped  in  gum- 
water.  If  all  the  previous  operations  have  been  well  per- 
formed, the  ink  will  readily  leave  the  ground  of  the  print 
remaining  on  the  lines. 

The  less  friction  is  used  the  better ;  if  the  ink  does  not 
easily  leave  the  paper  where  it  ought  to  do  so,  the  print 
must  be  floated  once  more  on  the  warm  water,  face  down- 
ward, for  a  few  minutes. 

As  soon  as  the  ground  of  the  print  is  quite  cleared  of  ink, 
and  the  whites  appear  in  the  closest  parts  where  they  show 
on  the  original,  the  paper  is  thoroughly  washed  in  tepid 
water  to  remove  all  the  gum  from  the  surface,  so  that  no 
trace  remains.  It  is  then  dried  and  is  ready  for  transferring 
to  zinc  or  stone. 

Transference  of  the  Print  to  Zinc  or  Stone. 
The  plates  of  zinc  are  first  scraped  until  all  inequalities 
are  removed.  A  piece  of  a  saw-blade  makes  a  good  scraper. 
Let  it  be  four  inches  long  and  three  wide,  in  the  form  of  a 
rectangle.  Grind  the  long  sides  quite  flat  on  a  grindstone, 
so  that  these  surfaces  present  two  sharp  edges  for  scraping. 
Use  the  scraper  as  in  veneering.  When  the  surface  of  the 
zinc  is  thus  made  free  from  blisters,  scratches,  etc.,  grind  it 
down  flat  with  a  pumice-stone,  and  smooth  it  with  snake- 
stone.  Finally  it  is  grained  with  a  disk  of  zinc  four  inches 
in  diameter,  half  an  inch  thick,  and  fixed  to  a  handle,  by 


306  PEINTING  WITHOUT  THE  SALTS  OF  SILVER. 


rubbing  the  disk  with  a  circular  movement  over  the  surfaco 
with  fine  sand  and  water.  The  sand  is  passed  through  a 
wire  sieve  containing  from  eighty  to  one  hundred  and  twenty 
meshes  in  a  square  inch.  As  soon  as  this  operation  is  com- 
jDlete,  the  plate  is  thoroughly  washed  and  dried,  and  then 
used  immediately. 

Old  plates  are  first  cleaned  with  turpentine,  then  with  an 
alkali,  and  finally  with  a  mixture  of  equal  parts  of  sulphuric 
and  hydrochloric  acid  to  twelve  parts  of  water.  The  grain- 
ing, too,  is  repeated. 

The  bichromate  print  is  first  moistened  between  sheets  of 
damp  paper  for  a  few  minutes,  then  placed  face  downward 
on  the  zinc  plate,  with  two  or  three  sheets  of  paper  over  it, 
and  passed  through  the  press. 

If  the  transfer  print  is  not  more  than  three  or  four  days 
old,  it  will  be  sufficient  to  pass  it  through  once ;  but  an  old 
print,  on  which  the  print  has  had  time  to  harden,  will  re- 
quire to  pass  through  the  press  two  or  three  times. 

The  sheets  of  paper  covering  the  transfer  are  then  re- 
moved, and  the  latter  is  damped  with  a  wet  sponge  for  two 
or  three  minutes  ;  this  causes  the  gelatine  in  the  lines  to 
swell,  and  makes  the  ink  leave  them  more  readily. 

The  print  is  then  pulled  carefully  from  the  plate ;  and  near* 
]y  the  whole  of  the  ink  should  remain  on  the  zinc. 


Bruise  the  galls  in  a  mortar  and  steep  them  in  the  water 
for  twenty-four  hours ;  after  which  the  mixture  is  made  to 
boil  over  the  fire,  and  then  filtered. 


The  phosphoric  acid  is  prepared  in  the  following  manner : 
Take  a  bottle,  three  quarters  full  when  holding  a  pint  of 
water,  and  insert  sticks  of  phosphorus  in  the  water,  so  that 
parts  of  them  are  exposed  to  the  air  above  the  fluid.  An 
incision  is  cut  in  the  cork  to  let  in  air.  The  phosphorus 
thus  becomes  oxidized,  and  the  phosphoric  acid  is  dissolved 
by  the  water  below.  In  a  few  days  the  solution  is  suffi- 
ciently strong  for  use. 

The  etching  liquid  is  poured  on  the  plate,  and  spread  over 


Etching  of  the  Zinc. 
The  etching  liquid  is  prepared  as  follows : 


No.  1. 1 


4  ounces. 
3  quarts. 


(  Gum  water  of  the  consistence  of  cream, 

No.  2.  <  Decoction  of  galls,  

(  Phosphoric  acid,  


3  quarts. 
1  quart. 
3  ounces. 


PEINTING  WITHOUT  THE  SALTS  OF  SILVER.  307 


the  surface  with  a  sponge  or  camel's  hair  brush.  For  fine 
work  twenty  seconds  will  be  sufficient ;  whereas  strong  lines 
would  bear  the  action  of  a  minute  without  injury.  The 
etching  solution  is  next  removed  entirely  with  a  cloth  dipped 
in  water. 

Finally,  the  transfer  ink  is  cleared  from  the  plate  with  tur- 
pentine, or  if  the  design  is  weak,  with  turpentine  mixed  with 
olive  oil  and  gum- water.  The  plate  is  then  rolled  up  with 
printing  ink,  the  roller  being  very  thinly  and  evenly  coated 
with  it.  Impressions  can  then  be  printed  in  the  usual  man- 
ner; fifteen  hundred  is  not  an  unusual  number  for  the  plate 
to  stand  without  sensible  deterioration. 

The  bichromate  print  can  be  transferred  to  a  lithographic 
stone  in  a  similar  manner. 

When  the  subject  admits  of  it,  paper,  enameled  with  zinc- 
white,  should  be  used,  as  the  impressions  produced  are  more 


perfect. 

Formula  for  Zinc  Enamel. 

-,  (  Russian  glue,  4  ounces. 

i>0,  1  (  Water,  3  quarts. 

Soak  for  several  hours,  and  then  dissolve  by  heat : 

No.  2.  ■{  Zinc  white,  (oxide  of  zinc,)     .    .    .    .    1£  pounds. 


Grind  with  water  on  a  slab,  mix  gradually  with  the  solu- 
tion of  glue,  and  pass  through  a  hair-sieve. 

This  enamel  is  communicated  to  the  paper  with  a  broad 
brush,  and  the  streaks  are  obliterated  with  a  flat  camel's 
hair  pencil.  A  second  coating  is  applied  in  a  similar  man- 
ner, when  the  paper  is  hung  up  to  dry. 

Sir  H.  James  remarks  that,  since  the  publication  of  the 
first  edition  of  the  process  above  copied  from  his  work,  he 
has  discovered  that  the  paper  coated  with  the  bichromate  of 
potassa  and  gelatine,  after  exposure  in  the  printing  frame  as 
already  described,  can  be  made  to  produce  transfers  with 
half  tone  or  gradation  of  shade  by  using  the  following  com- 
position for  the  ink,  and  washing  with  a  soft  sponge  moist- 
ened with  tepid  water  without  gum,  and  by  using  a  very 
gentle  hand  in  the  manipulation. 

Formula  for  Transfer  Ink. 


Lithographic  printing  ink,   8  ounces. 

Middle  lithographic  varnish,   4  ounces. 

Burgundy  pitch,   4  ounces. 

Palm  oil,   4  drachms. 

White  wax,   4  drachms. 

15 


308  PRINTING  WITHOUT  THE  SALTS  OF  SILVER, 


Photo-papyrography  by  Colonel  Sir  II.  James,  R.E. 

This  is  a  method  of  obtaining  a  single  copy,  or  a  copy 
or  two  of  some  manuscript,  plan  or  document,  etc.,  on 
paper,  without  incurring  all  the  trouble  of  preparing  either 
a  stone  or  a  plate  of  zinc.  For  this  purpose  a  nega- 
tive has  to  be  prepared,  by  copying  according  to  plans  al- 
ready minutely  described,  in  which  the  parts  are  not  later- 
ally inverted.  This  can  be  effected  too  by  simply  presenting 
the  glass  surface  (not  the  collodion  surface)  to  the  view,  etc., 
in  the  camera. 

With  such  a  negative  and  with  paper  already  prepared 
with  the  film  of  gelatine  and  bichromate  of  potassa,  a  posi- 
tive picture  can  be  obtained  in  carbon  ink,  laterally  inverted. 
The  image  is  brought  out  precisely  as  described  in  the  pro- 
cess of  photo-zincography.  It  is  then  placed  face  downward 
on  a  sheet  of  paper  and  passed  through  a  lithographic  press. 
A  sharp  and  clean  impression  is  thus  obtained. 

Colonel  Sir  H.  James  prepares  negatives  on  paper  covered 
or  flowed  with  the  wet  collodion  process.  The  sensitive 
ness  is  superior  to  that  of  collodion  on  glass,  and  the  nega- 
tives, when  waxed,  give  excellent  results. 

On  the  production  of  Photographs,  etc.,  on  Glass  in  JEnameo 
Colors  by  Joubert. 
A  piece  of  crown  or  plate  glass  is  selected  for  receiving 
the  photograph;  this  glass  must  be  as  free  as  possible  from 
all  flaws.  It  is  cleaned  as  usual,  and  flowed  with  the  fol- 
lowing solution: 

Saturated  solution  of  bichromate  of  ammonia,   .    5  drachms. 

Honey,  3  drachms. 

Albumen,  3  drachms. 

Distilled  water,  20  to  30  drachms. 

Mix  intimately  and  filter  in  the  dark-room.  As  soon  as 
the  plate  is  dry  by  means  of  artificial  heat  from  a  stove  or 
otherwise,  it  is  placed  in  contact  with  a  transparent  positive 
in  the  printing-frame.  An  exposure  of  a  few  seconds  to  the 
sun  will  show,  on  removal  from  the  frame,  a  faintly  indicat- 
ed negative  picture.  To  bring  it  out,  an  enamel  color,  in  a 
very  impalpable  state,  is  gently  rubbed  over  with  a  soft 
brush  until  the  whole  composition  or  subject  appears  in  a 
perfect  positive  form.  It  is  then  fixed  by  alcohol,  in  which 
a  small  quantity  of  acid,  either  nitric  or  acetic,  has  been 
mixed.  This  mixture  is  poured  over  the  whole  surface,  and 
drained  off  at  one  corner. 


PRINTING  WITHOUT  THE  SALTS  OF  SILVER.  309 

When  the  alcohol  has  completely  evaporated,  the  glass  is 
immersed  gently  and  horizontally  in  a  large  dish  of  clean  water, 
and  left  until  the  chromic  solution  is  dissolved,  and  nothing 
remains  but  the  enamel  color  on  the  glass ;  it  is  then  allowed 
to  dry  spontaneously  near  a  heated  stove.  When  dry  it  is 
ready  for  the  kiln. 

Enamel  of  any  color  may  be  used,  so  that  by  a  careful 
registering  a  variety  of  colors  can  be  printed  one  after  the 
other,  so  as  to  obtain  a  perfect  imitation  of  a  picture ;  also 
the  borders  of  any  description  can  be  subsequently  added, 
and  the  plate  again  submitted  to  the  fire. 

Naturally  ceramic  productions  can  be  thus  coated  with 
the  bichromate  photograph,  and  afterward  submitted  to  the 
fire  to  vitrify  the  image. 

White  enamel  is  glass  rendered  milky  by  fusion  with 
oxide  of  tin ;  it  forms  the  basis  of  many  of  the  colored 
enamels,  which  receive  their  tinge  from  the  metallic  oxides. 
Thus  the  purple  of  Cassius  (gold)  imparts  a  fine  ruby  tint. 
The  oxide  or  phosphate  of  silver  gives  a  yellow  color.  The 
oxides  of  iron  communicate  blue,  green,  yellow  and  brown, 
according  to  quantity  or  state  of  oxidizement.  The  oxides 
of  copper  produce  a  rich  green,  and,  when  mixed  with  tar- 
tar, a  red  color.  Antimony  yields  a  rich  yellow.  The  black 
oxide  of  manganese  in  excess  forms  black  glass  ;  in  smaller 
quantities,  various  shades  of  purple.  The  oxide  of  cobalt 
imparts  beautiful  blues  of  various  shades,  and  with  the  yel- 
low of  antimony  or  lead  it  produces  green.  Chrome  yields 
greens  and  reds  according  to  the  state  of  oxidizement. 


CHAPTER  XLI. 


STEBEOSCOPICITY. 

The  property  of  seeing  objects  in  relief  has  occupied  the 
attention  of  philosophers  from  the  earliest  periods  ;  and 
various  reasons  have  been  given  for  its  existence.  I  have 
no  hesitation  in  pronouncing  them  all  false,  excepting  the 
one  which  I  have  published  myself.  The  fact  exists  :  we 
see  objects  in  relief — what  is  the  meaning  of  this  expression  ? 
Simply  this  :  we  can  see  at  long  and  short  distances  at  the 
same  time.  But  the  eye  is  a  veritable  lens,  a  corrected  lens, 
and  is  subject  to  the  ordinary  laws  of  optics  ;  the  conjugate 
foci  of  objects  at  different  distances  are  not  on  the  same 
plane  but  at  different  distances  ;  the  retina,  therefore,  is 
not  a  surface,  it  is  a  substance  having  depth,  and  in  this 
depth  are  found  those  conjugate  foci  of  "the  different  objects, 
producing  thus  in  the  sensitive  and  transparent  substance  a 
miniature  solid  picture.  This  is  the  simplest  means  to  meet 
the  end  in  view  ;  and  the  Almighty  makes  use  of  the  sim- 
plest means,  and  these  means  I  think  I  have  understood  and 
analyzed.  To  see  long  and  short  distances  at  the  same  time, 
that  is,  to  see  objects  in  relief,  requires  the  possession  of  a  retina 
of  the  depth  of  about  of  an  inch  in  sensitiveness — now 
this  is  all  that  is  required — the  action  of  the  ciliary  nerve,  the 
motion  of  the  ciliary  muscle,  the  layer-like  structure  of  the 
crystalline  lens,  the  action  of  the  various  straight  and  oblique 
muscles  of  the  eye,  the  effect  of  the  will,  of  the  optic  arteries, 
and  numerous  other  contrivances,  all  these  are  not  required 
in  the  production  of  this  happy  effect. 

Euclid,  it  appears,  though  I  know  not  where,  attributes 
this  phenomenon  to  the  simultaneous  impression  of  two  dis- 
similar images  of  the  same  object  in  either  eye  of  the  observer. 

Arago  writes  that  when  we  see  an  entire  object,  the  phe 
nomenon  is  attributable  to  the  rapidity  of  the  action  of  the 
eye  passing  in  quick  succession  from  one  part  to  another. 

Pouillet's  theory  is  this  :  he  says  that  the  crystalline  lens* 
consists  of  ellipsoidal  layers  superposed  one  over  the  other, 


STEEEOSCOPICITY. 


311 


endowed  with  the  property  of  acting,  that  is,  of  refracting 
light  independently  of  each  other,  or  simultaneously. 

Some  authors  maintain  that  the  crystalline  lens  is  moved 
by  the  ciliary  muscle  from  or  toward  the  retina  with  great 
rapidity  during  the  action  of  the  perception  of  relief. 

Some  maintain  that  the  cornea  is  made  to  change  its  form 
>y  the  instrumentality  of  some  muscular  action  and  thus  to 
accommodate  itself  to  different  distances,  or  to  compensate 
for  the  change. 

Others  again  entertain  the  hypothesis  that  the  eye-ball  is 
either  elongated  or  compressed  by  some  muscular  action, 
just  as  the  distance  is  shorter  or  longer. 

As  I  said,  all  these  hypotheses  seem  to  be  false,  because  the 
minutest  investigations  have  not  yet  discovered  that  the  eye 
is  elongated  or  compressed)  that  the  crystalline  lens  is  ad- 
vanced or  drawn  back,  that  the  crystalline  lens  is  endowed 
with  independent  optical  layers,  that  the  ciliary  muscle  acts 
as  described,  that  the  cornea  is  in  any  way  changed  during 
the  act  of  any  perception.  On  the  contrary,  it  is  known  to 
be  a  positive  fact,  that  a  single  eye  has  a  correct  perception  of 
relief — that  many  animals,  such  as  ducks,  fish,  etc.,  have 
their  eyes  located  in  such  a  position  as  not  to  allow  the 
simultaneous  action  of  either  eye  on  all  occasions  ;  it  is  sup- 
posed, however,  they  see  as  perfectly  as  human  beings.  It 
is  a  well-known  fact  that  we  can  see  near  and  distant  objects, 
as  for  instance,  the  moon,  a  cloud,  a  church  steeple,  and  the 
branches  of  a  tree  close  by,  without  any  change  of  the  eye, 
and  without  any  effort.  It  has  been  furthermore  ascertained 
by  microscopical  examinations  that  the  retina  has  thickness, 
transparency  through  this  thickness,  and  is  constituted  of  a 
conical  or  stick-like  juxta-collocation  of  nervous  material 
from  before  backward,  which  we  have  a  right  to  suppose 
sensitive  to  the  impressions  of  light  throughout.  With  such 
a  constitution  of  nerves  the  problem  of  long  and  short  dis- 
tance, or  the  problem  of  seeing  in  relief,  is  solved. 

The  problem  of  seeing  pictures  in  relief,  depends  primari- 
ly upon  the  property  which  the  eye  possesses  of  seeing 
objects  in  relief ;  for  if  the  eye  were  not  endowed  with  this 
power,  pictures  as  well  as  objects  would  be  seen,  as  it  were, 
projected  flat  on  the  ground  glass  of  the  camera.  This  de- 
pends secondarily  on  the  combined  action  of  two  eyes  ;  for 
a  single  eye  can  by  no  contrivance  see  any  picture  optically 
in  relief. 

It  appears  that  Leonardo  da  Vinci  has  touched  upon  the 
subject  of  binocular  vision  in  one  of  his  manuscripts.  This 


312 


STEREOSCOPICITY. 


distinguished  painter  and  scholar  was  born  in  1452.  There 
is  nothing  positive  in  anything  he  has  left  us  about  the  pow- 
er and  rationale  of  seeing  pictures  in  relief. 

The  same  may  be  said  also  of  Giovanni  Battista  Delia 
Porta  and  of  Francis  Aguillon,  who  both  seem  to  have  had 
some  knowledge  of  binocular  perception. 

The  first  definite  and  positive  acquaintance  with  this  pe- 
culiar property  is  of  modern  date  and  is  mentioned  in  1832 
in  the  third  edition  of  Mayo' s  Outlines  of  Human  Physiolo- 
gy. Wheatstone's  reflecting  stereoscope  appeared  in  1838  ; 
it  appears  from  the  evidence  of  Newmann,  of  Regent  street, 
London,  that  Wheatstone  was  acquainted  with  a  refracting 
prism  that  would  produce  the  same  effect.  Brewster's  refract- 
ing stereoscope  appeared  in  1850.  Since  its  discovery  by 
Brewster  and  its  manufacture  originally  by  the  celebrated 
opticians,  Soleil  and  Dubosc  in  Paris,  stereoscopicity  has  oc- 
cupied the  attention  of  philosophers  and  amused  the  public  as 
much  as  photography  itself,  which  has  been  the  means,  in 
its  turn,  of  rendering  the  stereoscopes  so  popular.  Without 
photography  the  stereoscope  would  be,  like  the  kaleidoscope, 
a  mere  philosophical  toy. 

The  way  in  which  photography  has  extended  the  influence 
of  stereography  is  attributable  to  the  facility  it  gives  of  ob- 
taining consentaneously  two  dissimilar  pictures  of  the  same 
object  in  the  exact  conditions  as  they  would  be  depicted  by 
either  eye  of  the  spectator  ;  for  it  is  a  well-known  fact  now 
that  these  pictures  are  endowed  with  differences  depending 
upon  the  parallax  of  the  object  on  the  base  line  between  the 
two  eyes  ;  the  greater  the  parallactic  angle,  the  greater  the 
angular  displacement  of  either  picture  in  reference  to  the 
other. 

For  example,  let  a  spectator  stand  before  a  pane  of  glass 
looking  upon  a  church  for  instance.  At  the  distance  of 
distinct  vision  from  the  glass  fix  a  metallic  plate  containing 
two  small  apertures,  separated  by  a  distance  equal  to  that 
between  the  two  eyes.  Let  the  observer  now,  by  means  of 
a  style  dij^ped  in  thick  printer's  ink,  trace  the  outline  of  the 
church  on  the  glass  as  seen  through  the  aperture  of  the  right 
eye ;  in  like  manner,  let  him  do  the  same  through  the  aper- 
ture of  the  left  eye.  He  will  find  that,  instead  of  one  church, 
two  sketches  will  appear  on  the  glass  side  by  side,  endowed 
with  the  following  property  as  characteristically  distinct 
from  two  engravings  of  the  same  object  from  the  same  .plate. 
With  a  pair  of  compasses  measure  the  distance  between 
two  corresponding  points  on  the  church  which  are  nearest 


STEREOSCOPICITY. 


313 


to  the  observer ;  measure  also  the  distance  between  two  cor* 
responding  points  that  are  the  most  distant  from  the  observ- 
er, it  will  be  found  that  the  latter  measurement  will  exceed 
in  length  that  of  the  former  ;  and  that  this  result  will 
always  be  obtained  ;  that  is,  the  greater  the  distance  of 
certain  parts  of  the  objects  comprehended  in  a  picture  from 
the  point  of  observation,  the  greater  the  difference  of  dis- 
tance between  two  corresponding  points  in  the  foreground 
and  two  in  the  distant  background.  It  will  be  found,  more- 
over, that  the  distance  between  two  corresponding  points 
which  are  very  remote  from  the  eyes,  or  properly  speaking 
at  an  infinite  distance,  is  equal  exactly  to  the  distance 
between  the  eyes  of  the  observer. 

The  parallactic  angle  is  that  angle  which  is  comprehended 
between  the  axes  of  the  eyes  converging  to  a  given  point ; 
and  the  distances  between  any  two  corresponding  points  is 
equal  to  twice  the  versed  sine  of  the  parallactic  angle  ;  but 
the  versed  sine  of  an  angle  is  complementary  to  the  sine, 
and  the  sine  varies  as  the  angle ;  thus,  therefore,  as  the 
sine  decreases,  the  versed  sine  increases ;  and  in  like  man- 
ner the  distances  between  corresponding  points  from  ante- 
rior to  remoter  positions  in  the  background  will  gradually 
increase.  Such  are  the  properties  inherent  in  the  two 
pictures  of  the  same  object  as  depicted  on  the  retina  of 
either  eye,  or  on  the  ground  glass  of  a  binocular  camera. 
Two  photographs  or  pictures  taken  as  thus  described,  side 
by  side,  are  the  mere  interception  of  rays  on  a  flat  surface 
as  they  proceed  from  the  object.  It  is  natural  therefore  to 
suppose  that  these  pictures,  when  beheld  by  the  eyes,  ought 
to  give  an  impression  of  the  reality  in  relief.  By' a  minute 
investigation  of  the  subject  it  is  ascertained  that  conditions 
arise  for  the  effectuation  of  this  result,  which  at  the  first 
sight  are  not  anticipated.  One  condition  is  to  obtain  the 
same  convergence  of  the  axes  of  the  eyes  as  existed  when 
the  pictures  were  taken.  To  obtain  this  convergence  is  an 
effort  for  the  eyes  ;  and  on  this  account  there  are  but  few 
persons  who  possess  such  perfect  command  of  their  eyes 
as  to  secure  the  right  convergence  for  given  pictures.  It 
is  far  from  being  absolutely  necessary  that  the  convergence 
should  be  exactly  the  same  as  existed  originally  when  the 
photographs  were  taken  ;  there  are,  however,  certain  limits 
on  either  side,  that  is,  it  may  be  a  little  either  greater  or 
less  than  that  of  the  parallactic  angle. 

The  object  of  this  convergence  is  a  very  essential  point  in 
binocular  perception  producing  relief ;   and  the  rationale  of 


314 


STEREOSCOPICITY. 


this  perception  of  relief  is  not  lucid  on  other  grounds  than 
that  which  admits  of  the  production  of  a  virtual  solid  image 
in  space,  either  at  a  distance  beyond  the  pictures  or  in  front 
of  them.  Such  solid  images  are  formed  in  space  by  the 
intersection  of  the  rays  that  proceed  from  the  corresponding 
points  in  either  picture  ;  for  these  rays,  when  they  pass  the 
optic  centers  of  the  eyes,  form  different  parallactic  angles, 
according  as  the  distances  apart  are  different,  and  thus  in- 
tersect at  variable  distances  corresponding  with  the  points 
in  the  real  object  from  which  the  pictures  were  taken. 

Some  eyes  have  a  very  great  facility  of  converging  their 
axes ;  in  which  case  the  rays  from  corresponding  points  in- 
tersect in  front  of  the  pictures  and  very  nearly,  if  not  exactly, 
at  a  distance  half-way  between  the  pictures  and  the  eyes ; 
in  this  case,  (as  may  be  seen  on  referring  to  this  subject 
discussed  at  large,  page  73,  etc.,  Vol.  XIV.  of  Humphrey's 
Journal)  the  effect  of  relief  is  inverted,  the  most  distant 
points  being  projected  forward,  whilst  the  anterior  points 
are  seen  in  the  extreme  background.  This  is  the  natural 
consequence  of  the  intersection  of  lines  at  angles  that  depend 
upon  the  peculiar  distance  apart  of  the  corresponding  points 
in  the  pictures. 

Where  eyes  do  not  possess  this  great  degree  or  facility 
of  convergence,  the  intersections  will,  with  the  same  degree 
of  geometrical  consequence,  take  place  beyond  the  pictures 
and  at  variable  distances  beyond.  The  solid  picture  in  this 
case  will  not  be  inverted  ;  but  it  will  vary  in  magnitude  ac- 
cording as  the  intersections  occur  nearer  to  the  pictures  or 
farther  from  them.  Persons,  therefore,  endowed  with  this 
less  degree  of  convergence,  have  the  pleasure  of  beholding 
a  magnified  solid  picture,  of  which  the  magnitude  is  some- 
times very  great ;  whereas,  those  whose  optical  axes  can 
easily  converge,  see  a  solid  image  uniformly  of  half  the  size 
of  the  pictures,  but  which  is  on  this  account  very  sharp  and 
pleasing. 

All  eyes  can  be  tutored  with  very  little  difficulty  to  re- 
ceive this  impression  of  relief  from  two  photographs  pos- 
sessing the  conditions  required. 

In  order  that  the  solid  picture  in  the  latter  case  shall  be 
direct,  that  is,  not  pseudoscopic,  the  pictures  must  be  invert- 
ed, the  left  being  pasted  upon  the  right  side  ;  and  the  right 
on  the  left  side.  Two  photographs,  so  mounted,  I  have  de- 
nominated a  Strabonic  Stereograph,  to  distinguish  it  from 
the  ordinary  stereograph. 

Another  condition,  in  order  to  see  pictures  in  relief,  by 


STERJEOSCOPICITY. 


315 


the  binocular  perception,  is  the  cosentaneous  independent 
action  of  either  eye.  From  this  circumstance  either  eye 
beholds  the  two  images  ;  but  the  two  interior  ones  intersect, 
are  therefore  superimposed  and  form  thus  only  one  image, 
which  is  the  solid  image ;  the  two  outside  images  are  flat, 
and  do  not  attract  the  attention  to  any  great  extent,  by  rea- 
son of  the  superior  brilliancy  of  the  middle  picture.  The 
rationale  of  this  delightful  phenomenon,  as  hitherto  given  in 
all  our  text-books  on  the  subject,  is  so  far  erroneous,  from 
the  fact  that  it  is  asserted  that  each  eye  sees  its  correspond- 
ing picture  as  the  object  was  seen  when  the  pictures  were 
taken.  If  this  were  true,  we  ought  to  see  only  the  solid 
image,  and  not  the  two  outside  flat  pictures. 

All  the  instruments,  called  stereoscopes,  are  mere  optical 
contrivances  whereby  in  the  first  place  the  requisite  con- 
vergence is  obtained  with  facility ;  secondly,  they  magnify 
the  image  in  relief ;  and  thirdly,  they  shut  off  the  two  out- 
side flat  pictures.  They  are  not  essential  at  all  to  the  per- 
ception of  relief  furthermore  than  as  accessories.  The  phi- 
losophy of  stereoscopicity  is  very  simple,  it  is  founded  solely 
on  the  production  of  intersections  of  rays  from  corresponding 
points  of  two  pictures,  the  distance  of  which  points  must  be 
endowed  with  the  requisite  differences  ;  from  these  intersec- 
tions or  superimpositions  a  virtual  solid  image  is  formed 
which  is  then  regarded  as  a  real  object,  which  produces  the 
perception  of  relief  in  either  eye,  because  the  conjugate  pic- 
ture in  the  retina  is  also  solid. 

It  is  evident,  then,  that  a  single  eye  can  never  see  a  flat 
picture  in  relief,  because  the  requisite  intersections  can  not 
take  place ;  but  we  are  by  no  means  allowed  to  argue  from 
this  that  a  single  eye  can  not  appreciate  relief  or  distance 
in  real  objects,  or  that  relief  is  the  result  of  binocular  per- 
ception. This  is  an  absurdity  into  which  many  investiga- 
tors of  nature  have  fallen  ;  they  have  not  comprehended  the 
true  origin  of  this  perception,  which  depends  upon  the  sen- 
sitiveness of  the  retinal  film  through  a  certain  thickness,  and 
not  alone  on  a  surface. 

Eyes  may  be  tutored  to  see  two  photographs  in  relief  by 
the  following  expedients,  and  without  the  aid  of  stereoscopes. 

All  persons  accustomed  to  close  reading  or  writing,  or 
to  the  use  of  magnifying  spectacles  are  more  inclined  to  see 
strabonically  than  otherwise.  They  can,  in  plain  language, 
easily  squint  inwardly  and  see  the  end  of  the  nose. 


316 


STEEEOSCOPICITY. 


Strdbonic  Stereograph. 

In  the  first  place,  therefore,  prepare  a  number  of  strabonic 
stereographs  of  architectural  structures,  as  follows  :  "  Take 
the  ordinary  stereographs  of  the  views  in  question  and 
throw  them  into  a  pail  of  water  until  the  photographs  easily 
separate  from  the  mounts.  Remove  the  photographs,  and 
passing  over  the  backs  writh  a  sponge  dipped  in  starch  paste, 
transpose  them  upon  the  original  mounts  or  upon  new  ones  ; 
that  is,  fix  the  right-hand  photograph  on  the  left  side,  and  vice 
versa.  The  student  next  has  to  learn  to  see  double.  This  is 
effected  by  holding  up  the  thumb  before  the  eyes,  so  as  to  see 
two  thumbs  ;  when  he  is  expert  at  this,  let  him  next  hold  up 
in  front  of  his  eyes,  at  the  regular  reading  distance,  both  his 
thumbs,  and  try  if  he  can  see  four  thumbs.  As  soon  as  this 
is  effected,  then,  by  bringing  the  thumbs  closer  together,  so 
that  their  distance  apart  is  about  two  inches  and  a  half,  the 
two  middle  ones  can  be  made  to  overlap  each  other,  where- 
by three  thumbs  w7ill  appear.  The  difficulty  is  now  over- 
come ;  for  the  eyes,  when  well-practised  in  this  strabonic 
exploit,  are  prepared  for  regarding  a  stereograph  which  is 
mounted  as  above  described,  when,  with  a  little  patience, 
three  photographs  will  appear,  of  which  the  middle  one 
will  be  very  distinct,  finely  defined,  and  in  full  and  natural 
relief,  exhibiting  all  the  solidity  of  reality. 

The  two  outside  pictures  are  indistinct,  and  the  eyes  will 
soon  learn  to  neglect  them  ;  or  they  may  be  entirely  removed 
from  the  field  of  view  by  the  use  of  a  frustum  of  a  pyramid 
formed  of  cardboard,  whose  height  is  equal  to  half  the  dis- 
tance of  distinct  vision,  that  is,  half  the  reading  distance; 
the  side  of  its  upper  base  one  inch  and  a  quarter,  and  that 
of  the  lower  three  inches.  By  placing  the  lower  base  next 
the  eyes  and  looking  through  it,  the  stereoscopic  picture  will 
appear  alone  and  distinct.  A 

The  second  method  is  founded  on  a  reverse  principle,  that 
is,  by  excluding  the  rays  of  light  from  the  middle  of  the 
field  of  view,  comprehending  a  space  of  one  inch  and  a  quar- 
ter square.  This  is  effected  by  placing  a  piece  of  cardboard 
of  this  width  in  the  middle,  half-way  between  the  eyes  and 
the  photographs,  of  which  the  latter  are  fixed  at  the  regular 
reading  distance  ;  or  the  same  object  can  be  effected  as  fol- 
lows :  Take  a  slip  of  wood  about  two  feet  long,  two  inches 
wide  and  one  inch  thick;  take  secondly,  a  piece  of  card- 
board of  the  size  of  a  stereograph,  and  bisect  the  two  par- 
allel sides  and  the  two  parallel  ends,  and  join  the  points  of 


STEREOSCOPICITY. 


317 


bisection.  Where  these  lines  meet  we  have  the  center  of 
the  cardboard.  From  this  point  right  and  left  on  the 
larger  line,  mark  off  a  space  one  inch  and  a  quarter  in  length, 
and  at  either  extremity  thus  marked  off  draw  a  circle  half 
an  inch  in  diameter.  Lay  the  slip  of  wood  on  its  flat  sur- 
face on  a  table,  and  tack  the  piece  of  cardboard  to  one  end 
of  the  slip  at  right  angles  to  the  table,  with  an  equal  portion 
of  cardboard  projecting  at  either  end.  Previously,  however, 
the  wide  surface  of  the  slip  must  be  divided  longitudinally 
into  two  halves,  by  running  a  saw  from  end  to  end  so  as  to 
form  a  groove  about  a  quarter  of  an  inch  deep  ;  and  at  a 
distance  from  the  cardboard,  at  the  end,  equal  to  the  reading 
distance,  another  groove  is  sawed  at  right  angles  to  the  for- 
mer and  of  the  same  depth ;  in  the  latter  groove  an  ordinary 
stereograph  is  placed,  and  along  the  longitudinal  groove  a 
piece  of  cardboard  at  right  angles  to  it.  ISTow  let  the  ob- 
server look  through  the  two  apertures  at  the  stereograph ; 
it  is  evident  that  the  right  eye  can  see  only  the  right  photo- 
graph, whilst  the  left  eye  is  restricted  in  like  manner  to  the 
left.  By  concentrating  the  individual  attention  of  each  eye 
to  its  respective  picture,  by  pressing  the  external  parts  of 
the  ball  of  either  eye  with  the  fingers,  or  by  compressing 
the  eyes  as  in  frowning,  the  two  pictures  may  be  caused  to 
overlap  each  other,  when  a  new  picture  will  appear  possess- 
ed of  the  full  stereoscopic  effect,  apparently  of  a  larger  size 
than  the  originals.  The  magnitude  in  this  case  will  vary 
with  the  angle  of  convergence  ;  if  this  should  happen  to  be 
the  same  as  that  formed  by  the  axes  of  the  eyes  or  the 
lenses  when  the  pictures  were  taken,  the  solid  picture  will 
be  of  the  same  size  as  the  apparent  size  of  the  object  from 
which  the  photographs  were  taken ;  at  all  other  degrees 
of  convergence  the  magnitude  will  vary. 

Now  the  solid  picture,  produced  by  either  process,  can  be 
magnified  ad  libitum  by  means  of  eye-lenses  or  spectacles  ; 
and  when  these  eye-glasses  are  fixed  in  proper  receptacles, 
they  are  then  denominated  refracting  stereoscopes ;  but  it 
will  be  seen  that  they  are  fir  from  being  indispensable  ;  they 
are,  in  fact,  mere  accessories. 

The  differences  of  distance  between  the  corresponding 
points  on  two  photographs  taken  stereographically,  being 
functions  of  the  parallactic  angle,  can  be  easily  calculat- 
ed, and  consequently  artificial  stereographs  can  be  deline- 
ated geometrically.  The  results  drawn  from  such  calculations 
furnish  means  for  detecting  the  inherent  properties  ot  stereo- 
tjcopicity  or  their  total  absence  in  any  given  photographs  or 


318 


STEREOSCOPICITY. 


designs.  In  this  way  it  was  conclusively  determined  that 
the  drawings  of  Chimenti  were  not  stereoscopic.  Pages  of 
print  can  be  set  stereoscopically,  so  that  one  line  alternately 
stands  above  the  other,  or  in  any  way  whatever.  The  fol- 
lowing is  a  typographic  stereograph.  It  is  formed  by  set- 
ting the  alternate  lines  at  different  distances  from  one  anoth- 
er ;  that  is,  the  distance  from  T  to  T  in  the  first  lines  is 
greater  by  about  one  sixteenth  of  an  inch  than  the  distance 
from  H  to  H  in  the  second  lines  ;  and  all  the  rest  are  set  ac- 
cordingly. Viewed  by  the  stereoscope  the  odd  lines  will  be 
seen  standing  far  back  behind  the  even  lines ;  an  increase  of 
difference  will  throw  the  odd  lines  still  further  back  into  the 
background.  An  irregularity  of  difference  produces  an  ir- 
regularity in  the  relief. 


SIBEEOSCOPIOITT. 


319 


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CHAPTER  XLH. 


CELESTIAL  PHOTOGRAPHY. 

Within  the  last  few  years  the  importance  of  the  applies- 
cation  of  photography  to  astronomical  investigations,  as 
well  as  to  meteorology,  has  been  recognized  by  natural  phi- 
losophers as  a  definite  help-mate  in  the  prosecution  of  these 
studies.  This  application  consists,  when  referred  to  astron- 
omy, in  obtaining  photographs  and  stereographs  of  the  moon 
in  its  various  phases,  of  the  sun,  of  the  planets,  and  of  the 
comets;  and,  when  referred  to  meteorology,  in  obtaining 
photographic  delineations  of  the  different  classes  of  clouds ; 
of  the  aurora  borealis  in  its  various  configurations,  of  me- 
teors, halos,  water-spouts,  paraselenes,  etc. 

For  this  purpose  the  various  forms  of  telescopes,  both  re- 
flecting and  refracting,  may  be  employed,  which  are  used  in 
observatories.  Refracting  telescopes,  from  the  fact  of  their 
objectives  being  corrected  for  the  luminous  part  of  the  spec- 
trum, are  far  from  being  corrected  for  photographic  purposes  ; 
and  the  ground  glass  has  sometimes  to  be  moved  as  much  as 
an  inch  from  the  position  of  the  luminous  focus  before  the  ac- 
tinic focus  is  arrived  at.  Reflecting  telescopes,  on  the  con- 
trary, not  decomposing  light,  have  to  undergo  no  correction 
for  actinism.  For  amateur  astronomical  photographers  sil- 
vered glass  mirrors,  as  recommended  by  Steinheil,  are  most 
easily  constructed,  are  comparatively  cheap,  and  from  their 
lightness  very  manageable.  These,  when  properly  mounted, 
will  give  a  picture  of  the  moon,  etc.,  of  a  magnitude  vary- 
ing with  the  focal  length  of  the  mirror.  The  ground  glass 
is  placed  in  the  principal  focus  of  the  objective  or  reflector, 
and  has  a  motion  by  which  it  can  be  adjusted  to  accuracy. 
In  such  cases  the  eye-pieces  are  removed.  When  the  opera- 
tion is  not  instantaneous,  the  telescopes  have  to  be  furnished 
with  clock-work,  by  means  of  which  the  axis  of  the  body 
photographed  can  always  be  made  to  coincide  with  the  axis 
of  the  telescope,  during  the  time  of  exposure. 

We  are  indebted  to  Messrs.  Bond  of  Cambridge,  Crookes, 


CELESTIAL  PHOTOGRAPHY. 


321 


De  la  Rue,  Hartnup,  Forrest,  Edwards,  Berry,  Hodgson, 
Secchi,  etc.,  for  interesting  information  and  photographs  of 
celestial  objects. 

The  moon  naturally  claimed  the  first  attention  ;  the  Bonds 
were  the  first  to  obtain  a  daguerreotype  of  this  satellite; 
Messrs.  Hartnup,  Forrest,  Berry,  and  Edwards  obtained 
very  beautiful  photographs  on  collodion  of  the  moon  in 
1854,  of  an  inch  and  one  third  in  diameter,  which  they  after- 
ward magnified  a  few  diameters  on  another  collodion  plate, 
and  then  exhibited  the  photographic  representation  on  a 
large  screen  sixty  feet  in  diameter,  the  picture  having  been 
magnified  to  this  extent  by  means  of  a  magic  lantern. 

At  the  same  time  Mr.  Hartnup  suggested  a  plan  of  taking 
a  stereograph  of  the  moon,  by  first  taking  a  photograph  of 
this  luminary  twelve  hours  before  full,  and  then  twelve  hours 
after  full,  thus  changing  the  shadows  from  one  side  to  the 
other.  The  stereograph  was  successful,  and  exhibited  the 
moon  in  relief.  From  the  fact  that  the  moon  revolves  on 
her  axis  in  the  same  period  that  she  revolves  in  her 
orbit,  it  is  difficult  to  obtain  a  degree  of  parallax  by 
which  more  of  one  side  can  be  seen  at  one  time  than  at 
another  ;  but  the  axis  of  the  moon,  that  is,  the  moon  itself 
in  the  direction  of  its  axis,  has  a  sort  of  libration,  which 
brings  to  light  alternately  more  of  the  northern  parts  than 
of  the  southern.  By  taking  photographs  at  these  different 
periods  a  sufficient  amount  of  parallactic  angle  has  been 
obtained,  and  perfect  stereographs  have  been  the  result. 
The  moon  has  been  photographed  and  stereographed  in 
all  her  phases  ;  the  shadows  of  the  mountains  are  so  well 
delineated  in  these  different  phases  as  to  admit  an  accurate 
measurement  of  the  height  and  diameter  of  those  mountains. 

A  few  seconds'  exposure  with  a  good  equatorial  will,  in 
general,  give  a  tolerable  negative.  It  is  not  absolutely  ne- 
cessary to  be  furnished  with  a  telescope  in  order  to  get  a 
photograph  of  the  moon  ;  the  photographer  will  be  glad  to 
learn  that  a  long-focussed  view-tube  will  permit  him  to  ob- 
tain a  copy  of  this  bright  luminary,  of  about  half  an  inch  in 
diameter,  which  can  afterward  be  magnified  to  any  size  de- 
sired. The  only  difficulty  is  to  keep  the  moon  in  exactly 
the  same  position  of  the  ground  glass  for  a  number  of 
seconds. 

The  sun  is  easily  photographed,  because  the  operation  is 
instantaneous.  The  act  of  focussing  is  performed  by  placing 
a  piece  of  violet-colored  glass  over  the  opening  of  the  ob- 
jective, which  is  retained  there  during  the  exposure.  In 


322 


CELESTIAL  PHOTOGRAPHY. 


this  way  eclipses  of  the  sun  can  be  photographed  without 
that  immense  trouble  and  risk  which  have  been  so  often  re- 
ferred to  in  celestial  photography. 

The  stars  have  a  high  degree  of  photogenic  power,  and 
can  be  photographed  in  accordance  with  the  intensity  of  their 
light.  Mr.  Bond  has  endeavored  to  base  upon  this  power  a 
means  of  classifying  the  stars  into  magnitudes,  which  at 
present  are  quite  arbitrary. 

The  planets,  possessing  much  less  photogenic  power  than 
the  fixed  stars,  are  in  consequence  not  so  easily  photograph- 
ed ;  but  by  means  of  well-regulated  clock-work,  De  la  Rue 
has  succeeded  in  obtaining  very  excellent  photographs  of 
Jupiter  and  his  bands,  Saturn  and  his  rings,  as  also  a  stereo- 
graph of  Mars,  by  taking  two  photographs  at  an  interval  of 
two  hours,  and  others  of  Saturn  at  an  interval  of  three  years 
and  a  half. 

It  is  supposed  there  are  planets  nearer  to  the  sun  than 
Mercury,  which  have  not  been  discovered  by  reason  of  their 
proximity  to  the  solar  orb  :  it  is  hoped,  however,  by  means 
of  photography  to  settle  this  supposition ;  for  if  at  any  time 
in  any  of  the  numerous  photographs  which  are  taken  of  the 
sun,  a  small,  round  black  speck  should  be  discovered,  the 
conclusion  of  the  existence  of  another  inferior  planet  would 
soon  be  drawn. 

De  la  Rue  is  prosecuting  this  branch  of  photography  and 
astronomy  with  great  zeal  and  success ;  his  labors,  too,  are 
highly  appreciated.  The  Astronomical  Society  of  London 
have  conferred  upon  him  their  annual  large  medal  as  a  token 
of  their  high  appreciation  of  his  merits  and  the  results  of 
bis  labors. 


CHAPTER  XLIII. 


HELIOCHROMY,  OR  THE   ART   OF   TAKING   PHOTOGRAPHS  IK 
NATURAL  COLORS. 

Sir  John  Herschel  observed  in  1840,  that  paper,  prepared 
with  chloride  of  silver  and  blackened  in  the  sun,  when  ex- 
posed beneath  red  or  blue  glass,  assumed  the  respective  color 
of  the  glass;  and  Edmond  Becquerel  in  1847  and  1848  pro- 
duced all  the  colors  of  the  spectrum  on  a  prepared  silver 
plate,  which  were  permanent  as  long  as  the  plate  was  kept 
in  the  dark.  The  surface  was  sensitized  by  immersing  the 
plate  either  in  a  solution  of  a  bichloride,  or  in  chlorine  water. 

Niepce  de  St.  Victor,  following  in  the  steps  of  Becquerel, 
is  obstinately  persevering  in  his  attempts  to  fix  the  colors 
which  can  already  be  obtained.  The  production  of  colors  is 
a  fact ;  the  fixation  of  colors  is  still  a  problem  unsolved. 

The  plate  for  heliochromic  purposes  is  best  prepared  in  the 
following  manner :  A  common  daguerreotype  plate  is  var- 
nished on  the  copper  side.  In  one  corner  a  hole  is  bored  in 
order  that  the  plate  can  be  suspended  on  a  silvered  copper 
wire,  which  is  the  positive  pole  of  a  galvanic  battery.  A 
small  plate  of  platinum  soldered  to  a  copper  wire  forms  the 
negative  or  zinc  pole.  As  soon  as  the  battery  is  in  working 
condition,  insert  the  two  poles  at  the  proper  distance  in  a 
vessel  containing  a  mixture  of  one  part  of  hydrochloric  acid 
and  eight  parts  of  water.  By  the  electrolytic  decomposition 
hydrogen  affects  the  negative  pole  and  is  given  off  there, 
whereas  chlorine  goes  to  the  silvered  plate,  combines  with 
the  silver,  and  forms  a  chloride.  The  operation  is  best  per- 
formed in  the  dark-room.  The  amount  of  deposition  is  re- 
cognized by  the  different  shades  of  color  which  the  plate  as- 
sumes.   The  thinner  the  film,  the  more  sensitive  it  is. 

Niepce  de  St.  Victor  has  recommended  the  production  of 
this  sensitive  film  by  immersing  the  plate  in  soluble  bichlo 
rides,  or  in  chlorides  in  combination  with  copper  salts. 

In  whichever  way  prepared,  the  plate  is  dried  over  the 
flame  of  a  spirit-lamp,  and  the  surface  is  gently  brushed  over 


324 


PHOTOGRAPHS  IN  NATURAL  COLORS. 


with  a  tuft  of  cotton,  in  order  to  remove  a  downy  substance 
arising  from  impurities. 

If  this  plate  be  exposed  to  a  diffused  light,  the  film  assumes 
a  grayish  violet  tinge ;  but  if  it  be  exposed  to  a  well-defined 
and  very  luminous  spectrum,  it  receives  an  impression  of  the 
various  colors  of  this  spectrum,  but  not  with  the  same  facil- 
ity. The  orange,  the  yellow,  and  the  red  are  the  first  colors 
that  appear,  and  the  first  to  darken  and  to  become  gray  by 
a  continued  action.  Beyond  the  red  a  rosy  hue  is  made 
manifest,  but  this  darkens  the  first  of  all.  The  blue,  the 
green,  and  the  violet  are  the  most  vivid.  Beyond  the  ter- 
mination of  the  violet  part  of  the  spectrum  there  is  a  decom- 
position of  a  gray  color. 

By  keeping  the  prepared  plates  exposed  to  a  temperature 
of  about  100°  for  forty-eight  hours  in  a  stove,  or  to  the  rays 
of  the  sun  beneath  a  piece  of  red  glass,  the  film  becomes 
much  more  sensitive,  and  not  only  reproduces  the  spectrum 
but  receives  an  impression  from  white  light. 

If,  when  the  plate  leaves  the  electrolytic  bath,  it  be  sim- 
ply dried,  without  raising  the  temperature  to  such  a  degree 
as  to  change  the  color  of  the  film,  and  after  this  the  plate 
be  exposed  beneath  a  colored  engraving,  a  reproduction  of 
these  colors  will  soon  be  effected ;  some  of  these  are  some- 
times latent,  whilst  others  are  brilliantly  manifest.  Those 
which  are  latent  can  be  developed  by  simply  rubbing  the 
surface  gently  with  a  tuft  of  cotton  impregnated  with  am- 
monia, which  has  been  previously  used  for  cleaning  a  plate. 
It  is  hence  evident  that  a  colored  image  is  already  produced, 
which  may  be  partially  manifest  and  partially  latent. 

Two  very  important  problems  remain  to  be  solved  :  to 
find  means  of  developing  the  whole  of  the  image  at  once  in 
all  its  colors,  and  of  fixing  it  when  developed.  Some  colors 
can  be  always  reproduced,  whilst  others  are  but  partially 
obtained.  None  of  the  colors  as  yet  can  be  rendered  per- 
manent in  diffused  light.  This  branch  of  photography, 
therefore,  is  still  quite  imperfect.  It  is  difficult  to  form  an 
opinion  as  to  the  possibility  of  the  solution  of  this  interest- 
ing problem  ;  because  as  yet  no  clue,  no  rational  hypothesis 
can  be  given  of  the  cause  of  the  reproduction  of  the  colors 
in  question.  In  the  ordinary  positive  printing  on  the  chlo- 
ride of  silver,  the  cause  of  the  decomposition  is  probably  just 
as  little  understood ;  but  we  are  satisfied  with  almost  any 
theory  as  long  as  the  manipulation  is  definite  in  its  manage- 
ment, and  within  our  power  to  continue  or  restrain.  In  the 
reproduction  of  colors  these  characters  are  wanting,  and  we 


PHOTOGRAPHS  IN  NATURAL  COLORS. 


325 


are  hence  tempted  to  disbelieve  in  the  possibility  of  the 
effectuation  of  so  desirable  a  discovery.  On  the  other  hand, 
the  very  fact  that  colors  can  be  once  reproduced,  engenders 
faith  in  the  realization  of  the  great  object ;  and  because  a 
similar  and  apparently  equally  as  difficult  case  of  fixation 
of  a  fugitive  image  has  already  been  overcome,  hope  still 
points  to  the  goal  of  final  success. 

Our  knowledge  of  the  image-impressions  by  contact,  by 
the  influence  of  heat  and  of  electricity,  is  limited  simply  to 
the  recorded  facts,  for  which  as  yet  no  satisfactory  rationale 
has  been  assigned.  Probably  all  the  pictorial  representations 
of  objects  in  photography,  and  its  congene  branches,  develop- 
ed either  by  mercury,  pyrogallic  acid,  the  protosalts  of  iron, 
the  breath,  impalpable  powders,  etc.,  may  be  classified  in  one 
and  the  same  category,  of  which  the  cause  may  either  be  a 
molecular  or  polar  change — that  is,  either  an  absolute  change 
of  position  of  the  ultimate  atoms  in  the  aggregated  material, 
or  simply  a  change  in  the  attractions  of  these  atoms.  The 
hypothesis  thus  expressed  is  founded  upon  the  circumstance 
that  every  latent  image  is  developed  by  means  of  matter 
applied  to  the  film,  which  is  attracted  to  certain  parts  after 
exposure  by  apparent  predispositions  in  these  parts,  which 
have  been  superinduced  by  this  exposure ;  the  resulting 
pictures  are  combinations  of  the  new  and  applied  material 
with  the  original  matter  in  the  film.  By  an  extended  course 
of  definite  experiments  applied  understandingly  in  reference 
strictly  to  cause  and  effect,  we  have  a  right,  in  the  course  of 
time,  to  expect  a  definite  solution  of  these  wonderful  manifes* 
tations  of  the  presence  of  an  Omniscient  Intelligence. 


CHAPTEE  XLIV. 


IMPERFECTIONS   IN  COLLODION  NEGATIVES  AND  POSITIVES, 
AND  THEIR  REMEDIES. 

The  knowledge  of  an  imperfection  or  an  error  is  half  the 
correction.  We  must,  therefore,  first  know  what  the  fail- 
ures in  collodion  negatives  and  positives  are.  Their  enu- 
meration is  as  follows : 

Fogginess  ;  Spots  and  Apertures  ;  Ridges  and  TIndulating 
Lines  ;  Streaks  and  Stains  /  Feebleness  of  the  Image,  or 
Deficiency  of  Contrast  /  Harshness,  or  Excess  of  Contrast; 
Imperfect  Definition  /  Solarization  /  Tender  and  Rotten 
Films. 

Fogginess. — This  is  a  mist  or  veil-like  appearance  that 
covers  the  whole  negative ;  it  gives  it  a  foggy  or  clouded 
appearance.  This  imperfection  may  be  the  result  of  many 
and  various  causes,  as  for  instance  :  Diffused  light  in  the 
camera  through  holes  or  chinks  ;  reflections  from  white  or 
unblackened  surfaces  in  the  camera  ;  diffused  light  through 
apertures  or  chinks  in  the  door  behind  the  plate  in  the  plate- 
holder  ;  direct  rays  of  the  sun  through  the  objective  or  lens  ; 
an  alkaline,  neutral,  impoverished  or  contaminated  state  of  the 
nitrate  of  silver  bath  ;  a  similar  condition  of  the  collodion  ; 
certain  iodizers  in  the  collodion  and  at  certain  stages  of 
ripening  ;  diffused  light  in  the  dark-room  ;  too  intense  arti- 
ficial light  in  the  dark-room  ;  too  intense  a  development  ; 
fumes  of  ammonia,  of  turpentine,  of  tobacco,  of  hydrosul- 
phuric  acid,  and  probably  almost  of  any  other  volatile 
chemical  substance  in  the  developing-room  ;  imperfect 
cleanness  of  a  glass  plate  that  has  been  used  before ; 
the  use  of  gutta-percha  baths  and  dippers. 

Diffused  light  in  the  camera,  either  in  front  of  the  plate 
or  behind  it ;  Reflections  from  white  or  unblackened  sur- 
faces in  the  camera. — This  is  a  certain  cause  of  fogging,  and 
can  easily  be  remedied.  Examine  the  camera  carefully  for 
all  chinks  and  holes.    Some  photographers  are  very  care- 


IMPERFECTION'S  AND  THEIR  REMEDIES. 


327 


less  ;  they  screw  on  the  flanges  of  various-sized  tubes  on  the 
end  of  the  camera,  and  neglect  filling  the  apertures  left  by 
the  screws  when  withdrawn.  Chinks  occur  invariably  in 
cameras  made  of  green  wood  ;  and  the  bellows  part,  by 
frequent  adjustment,  sometimes  cracks.  The  plate-holder 
has  also  its  imperfections  ;  the  slide  sometimes  allows  the 
entrance  of  light  ;  the  apertures  at  the  bottom,  for  the  pas- 
sage of  accumulating  nitrate  of  silver,  are  frequently  left 
open  and  not  filled  with  sponge,  so  that  light  penetrates  in 
this  way.  The  door  behind  may  close  inaccurately ;  and 
the  plate-holder  may  slide  irregularly  and  not  fill  the  groove 
calculated  to  receive  it.  All  these  are  errors  or  defects  of 
workmanship,  which  must  and  can  be  avoided  or  remedied. 
Look,  therefore,  to  your  camera  first  in  the  search  of  chinks, 
cracks,  and  apertures  ;  secondly,  if  the  inside  surfaces  of 
the  camera  are  not  of  a  dead  black,  cover  them  with  un- 
glazed  black  woolen  or  cotton  cloth,  or  wash  them  over 
with  a  thick  solution  of  ink  or  lampblack. 

Direct  rays  of  the  sun  through  the  axis  of  the  lens. — 
Avoid  this  evil ;  like  many  other  troubles,  to  know  it,  is  its 
total  remedy. 

An  alkaline,  neutral,  impoverished  or  contaminated  state 
of  the  nitrate  of  silver  bath. — Immerse  a  piece  of  reddened 
litmus  paper  in  the  bath,  and  see  whether  it  changes  color, 
after  a  while,  to  a  blue — if  so,  the  bath  is  alkaline. 

First  remedy. — Make  a  mixture  of  six  drops  of  acetic 
acid  in  a  drachm  of  water,  if  you  are  taking  negatives,  and 
of  the  same  quantity  of  nitric  acid  and  water,  if  you  are 
taking  positives  ;  add  ten  drops  at  a  time  of  either  solution 
until  the  fogging  disappears.  Sometimes  even  more  acid 
may  be  required. 

Second  remedy. — Instead  of  adding  acid  to  the  bath,  add 
an  old  collodion  or  tincture  of  iodine  to  your  collodion  in 
present  use  ;  this  frequently  is  the  safest  plan  of  action. 

If  the  bath  is  impoverished,  it  will  at  the  same  time  be 
contaminated.  The  remedy  is  to  boil  it  some  time  in  a 
glass  flask  in  order  to  get  rid  of  the  ether,  alcohol,  and  the 
volatile  substances  produced  by  decomposition,  as  also  to 
coagulate  organic  matter ;  then  allow  the  bath  to  cool,  and 
filter.  To  the  filtrate  add  more  nitrate  of  silver  if  required. 
Placing  an  old  bath  in  the  sun  for  several  days  is  also  of 
great  assistance,  but  it  is  far  from  being  equal  to  boiling  or 
distilling. 

Certain  iodizers  in  the  collodion  and  at  certain  stages  of 
ripening. — Iodide  of  cadmium  alone  frequently  produces 


328  IMPERFECTIONS  AND  THEIR  REMEDIES. 


fogginess  ;  almost  any  new  and  limpid  collodion  has  the 
same  effect.  Add  iodide  of  ammonium  in  the  first  case,  and 
an  old  collodion  or  tincture  of  iodine  in  the  second  case  , 
the  sensitiveness  will  be  thereby  probably  diminished,  Avhilst 
the  condition  to  fog  will  be  removed. 

Diffused  light  in  the  dark-room,  or  too  intense  an  artificial 
light. — Place  the  artificial  light  behind  a  piece  of  ground 
glass,  and  do  not  bring  it  near  the  negative  until  the  latter 
is  thoroughly  fixed.  .  Diffused  light  must  be  locked  out  of 
the  room. 

Too  intense  a  developer. — In  summer  less  of  the  devel- 
oper, whether  of  iron  or  pyrogallic  acid,  or  more  of  the 
acid  is  required  than  in  winter,  otherwise  fogging  will  be 
the  consequence — the  property  of  acid  is  to  restrain  the  ac- 
tion of  the  developer  ;  use  your  judgment,  therefore,  and 
do  not  always  keep  to  the  same  amount  of  protosulphate  of 
iron,  or  pyrogallic  acid  to  the  ounce  of  water  in  all  seasons  ; 
nor  restrict  yourself  unconditionally  to  the  same  amount  of 
acid  in  the  developer. 

Fumes  of  ammonia,  etc. — Keep  your  dark-room  solely  for 
its  legitimate  purposes.  Keep  it  rigidly  clean  ;  perform  no 
chemical  experiments  in  it  ;  abjure  smoking  in  this  sanc- 
tum ;  do  not  sensitize  your  papers  or  fuminate  with  ammo- 
nia in  this  room  ;  make  no  manner  of  fumes  therein. 

Imperfect  cleanness  of  the  plate,  etc. — Wash  the  old  plates 
with  a  solution  of  salts  of  tartar  and  water  ;  if  this  does  not 
remove  the  adhering  dirt,  wash  it  with  dilute  nitric  acid, 
and  afterward  with  salts  of  tartar,  and  finally  clean  and 
polish  the  plate  with  rotten-stone  and  alcohol.  Some  old 
plates  that  have  lain  long  in  water  in  which  the  old  develop- 
ing solutions  have  been  thrown  I  have  never  succeeded  in 
cleaning  so  as  to  prevent  fogging  ;  they  are  contaminated  to 
the  backbone. 

The  use  of  gutta-percha  baths,  etc. — Instead  of  these,  use 
glass,  porcelain  or  photographic  ware  baths — the  latter  are 
very  highly  recommended  ;  I  prefer  glass  to  every  other 
material. 

Spots  and  Apertures. 

Opaque  and  transparent  specks  are  the  most  troublesome 
annoyances  in  the  collodion  negative  process,  and  occur  to 
every  photographer  more  or  less.  These  can  be  attributed 
to  various  causes,  but  seldom  for  the  time  being  to  the  right 
cause  ;  that  is,  we  know  in  general  what  will  cause  them, 
but  seldom  what  did  cause  them. 


IMPERFECTIONS  AND  THEIR.  REMEDIES.  329 

The  opaque  spots  may  be  caused  in  the  first  place  by  dust 
on  the  surface  of  the  glass  before  the  collodion  is  poured  on. 
The  remedy  is  simple  :  brush  off  the  dust  with  a  broad,  flat 
camel's  hair  pencil  just  before  the  collodion  is  applied. 

Secondly. —  Opaque  spots  may  be  caused  by  dust  on  the 
surface  of  the  collodion  ;  this  dust  may  be  deposited  either 
from  the  bath  itself,  previous  to  immersion  in  the  bath,  or 
in  the  camera  during  exposure.  That  which  is  deposited 
either  before  or  after  immersion,  are  the  organic  substances 
in  a  state  of  very  minute  division  floating  about  in  the  at- 
mosphere or  set  in  motion  within  the  camera  by  the  agita- 
tion produced  with  the  plate-holder.  This  is  perhaps  the 
most  fruitful  source  of  trouble,  which  is  of  two  kinds,  opaque 
and  transparent  spots.  The  particles  of  dust  attach  them- 
selves to  the  collodion  with  different  degrees  of  tenacity  ; 
where  the  tenacity  is  small,  the  dust  is  washed  off  in  the 
different  manipulations  of  developing  and  fixing,  and  the 
consequence  is  the  production  of  transparent  specks  ;  on 
the  contrary,  where  the  tenacity  is  great,  opaque  spots  are 
the  result ;  for  the  particles  remain  imbedded  after  the  final 
washing.  If  the  dust  be  deposited  from  the  bath  itself,  it 
may  arise  either  from  organic  materials,  in  the  atmos- 
phere or  from  an  excess  of  iodide  of  silver  in  the  bath,  in 
the  form  of  the  violet-colored  deposit  found  at  the  bottom 
or  on  .the  walls  of  the  bath.  The  remedy  is,  in  the  first  case, 
to  keep  your  room-floors  moist,  and  your  camera  perfectly 
free  from  this  enemy  by  dusting  and  sponging.  In  the  sec- 
ond place,  the  insoluble  deposit  in  the  bath  is  separated  by 
filtration  ;  the  bath,  too,  is  thoroughly  cleaned  by  a  sponge 
tied  to  the  end  of  a  rod,  which  can  be  made  to  enter  into  the 
angular  spaces  in  which  the  dust  is  deposited. 

Tliirdly. — Another  source  of  this  trouble  with  opaque 
spots  is  to  be  found  in  the  collodion,  which  contains  some- 
times undissolved  pyroxyline  in  the  form  both  of  dust  and 
fibres,  or  in  fine  organic  dust  from  impure  sources  of  mani- 
pulation. To  remedy  the  evil,  allow  the  collodion  to  settle 
thoroughly  and  use  only  the  clear  supernatant  part. 

Transparent  Spots. 

These  are  of  much  more  frequent  occurrence  than  opaque 
spots.  They  may  arise,  in  the  first  place,  from  undissolved 
particles  of  the  iodides  in  the  ether  and  alcohol  of  the  col- 
lodion ;  this  is  particularly  the  case  with  iodide  of  potassium 
in  anhydrous  alcohol ;  these  afterward  become  dissolved  in 


330  IMPERFECTIONS  AND  THEIR  REMEDIES, 

the  subsequent  operations.  The  remedy  is  a  drop  or  two  of 
water,  or  of  diluted  alcohol,  or  of  bromide  of  ammonium. 

As  remarked  in  reference  to  opaque  spots,  particles  of 
dust  in  the  camera  or  of  the  insoluble  iodide  of  silver  in  the 
bath,  adhering  to  the  surface  of  the  collodion,  produce  specks, 
both  opaque  and  transparent.  The  transparent  ones  result 
from  the  fact  that,  during  exposure,  and  the  dust  particles 
being  opaque,  they  prevent  the  rays  of  light  from  acting 
actinically  on  the  collodion  film  beneath,  and  then,  being 
washed  off  in  the  subsequent  manipulations  of  development, 
fixing,  intensifying,  and  washing,  they  leave  the  collodion  in 
those  parts  to  the  mercy  of  the  fixing  solutions,  which  ren- 
der them  quite  transparent.  The  remedy  is  to  keep  the  cam- 
era and  the  room  free  from  dust,  and  the  bath  from  insoluble 
particles  of  the  iodide  of  silver  or  organic  materials.  If  the 
bath  is  the  cause,  the  trouble  may  be  avoided  by  keeping  the 
plate  in  motion  during  sensitization. 

Another  cause  of  transparent  spots,  and  probably  a  very 
frequent  one,  is  to  be  attributed  to  a  crystalline  deposit  of 
iodo-nitrate  of  silver,  which,  as  the  bath  becomes  weaker,  is 
precipitated  in  a  crystalline  form  on  the  surface  of  the  collo- 
dion film.  This  form  of  deposit  occurs  with  an  old  bath. 
Its  remedy  is  to  precipitate  it  out  of  the  bath  by  adding 
water,  and  then  by  filtration.  Then  for  every  ounce  of  water 
thus  added  pour  in  after  filtration  the  same  amount  of  a  ni- 
trate of  silver  solution  to  take  its  place. 

When  the  bath  is  the  cause  of  transparent  spots,  a  small 
quantity  of  a  solution  of  chloride  of  sodium  (common  salt) 
thrown  in  is  found  to  be  of  great  benefit.  Chloride  of  silver 
and  nitrate  of  soda  are  formed  by  double  decomposition; 
the  insoluble  chloride  probably  carries  down  with  it  the  dust 
or  particles  which  are  the  cause  of  the  trouble,  or  the  nitrate 
of  soda  dissolves  them.  I  am  not  able  to  say  what  is  the 
true  explanation.  After  filtration  the  bath  is  raised  to  the 
proper  strength,  when  it  will  be  found  to  be  free  from  the  evil. 

Midges  and  Undulating  Lines, 
These  are  caused  by  the  too  great  consistency  of  the  col- 
lodion, and  are  found  in  the  direction  of  the  current  of  the 
collodion.  The  remedy  is  to  add  sufficient  ether  to  cause 
the  collodion  to  flow  smoothly,  easily,  and  uniformly  over 
the  plate.  The  mottled  appearance  sometimes  apparent  on 
a  collodion  film,  as  if  covered  with  flocks  of  wool,  is  owing 
also  to  the  thickness  of  the  collodion,  and  the  evil  is  remedied 
in  the  same  manner  as  the  ridges. 


IMPERFECTlOx^S  AND  THEIR  REMEDIES. 


331 


Streaks  and  Stains. 

Streaks  may  arise  from  an  irregularity  in  the  immersion 
of  the  plate  in  the  silver  bath,  or  in  withdrawing  it ;  the 
plate  has  to  be  immersed  or  withdrawn  without  any  stop- 
ping. Streaks  and  stains  are  produced,  too,  by  the  film  of 
dust  swimming  on  the  surface  of  the  vertical  bath,  which  is 
carried  down  on  the  collodion  when  the  plate  is  immersed. 

They  arise,  secondly,  from  the  irregular  flowing  of  the 
developing  solution ;  the  remedy  is  to  use  the  gutta-percha 
developing  dish  already  recommended  for  such  purposes. 
Another  remedy  may  be  a  proper  quantity  of  alcohol  added 
to  the  developer,  if  there  happen  to  be  a  sort  of  greasiness 
or  repulsion  in  the  collodion  film  to  the  developing  solution 
as  it  flows  along. 

The  part  upon  which  the  developer  first  comes  in  contact 
with  the  collodion  film  almost  invariably  exhibits  a  streak 
around  a  denuded  part,  as  if  the  developer  had  swept  off  the 
latent  image  in  that  part.  The  remedy  is  the  developing 
dish,  by  which  the  developer  acts  with  little  or  no  moment- 
um greater  at  one  part  than  at  another. 

A  sort  of  fortification  system  of  stains  and  streaks  arises 
from  the  want  of  cleanness  of  the  corners  of  the  plate-shield, 
from  an  inferior  quality  of  collodion,  from  the  unequal  dry- 
ness of  the  film  before  immersion  in  the  silver  bath,  as  well 
as  from  a  too  great  and  irregular  dryness  of  the  film  after 
exposure  and  before  development.  The  remedies  are  self- 
apparent  ;  avoid  the  causes. 

Stains  of  a  blue  color  arise  from  imperfect  washing  be- 
tween developing  and  fixing. 

Feebleness  of  the  Image,  or  deficiency  of  Contrast. 

A  new  collodion  will  very  frequently  be  one  cause  of  this 
trouble — the  materials  are  not  yet  ripe.  As  a  remedy,  add 
old  collodion,  or  wait  for  a  few  days,  until  the  collodion  is 
sufficiently  decomposed. 

Over-exposure  is  another  and  very  frequent  cause  of  a 
feeble  contrast  in  the  picture.  All  the  parts  are  developed 
simultaneously,  and  too  much  deposit  of  reduced  silver  is 
the  result  all  over  the  picture.  A  shorter  exposure  is  the 
remedy. 

Too  intense  a  developer,  or  a  developer  continued  too  long, 
fogs  the  picture  and  weakens  the  contrast. 

Imperfect  lighting  is  a  third  cause,  in  which  the  light  is 
either  small  in  quantity,  or  diminished  in  intensity  by  reason 
of  peculiarities  in  the  atmosphere. 
16 


332  IMPERFECTIONS  AND  THEIR  REMEDIES. 


Harshness,  or  Excess  of  Contrast. 
Under-exposure,  a  too  acid  bath,  a  too  acid  developer,  un- 
der-development,  an  old  and  insensitive  collodion :  all  these 
will  produce  pictures  of  mere  black  and  white ;  the  interme- 
diate tones  are  totally  wanting.  The  remedy  is  apparent ; 
use  it  as  the  case  maylbe. 

Imperfect  Definition. 

This  may  be  caused  by  the  want  of  coincidence  in  the  chemi- 
cal and  luminous  focus.  See  that  the  surface  of  the  ground 
glass  and  that  of  the  inserted  plate  have  exactly  the  same  dis- 
tance from  the  back  lens,  and  correct  this  evil  according  to 
rules  already  laid  down. 

The  want  of  sharpness  may  arise  from  careless  focussing, 
from  the  mobility  of  the  sitter  during  exposure,  from  a  change 
of  position  in  the  camera  when  inserting  the  sensitized  plate, 
or,  in  fine,  from  a  bad  lens.  The  remedy  in  every  one  of  these 
cases  is  obvious,  excepting  perhaps  in  the  last ;  for  the  pho- 
tographer may  not  always  be  in  a  condition  to  get  a  better 
lens.  The  only  and  most  advisable  remedy  in  this  case  is  to 
close  his  gallery  and  feign  sickness,  until  the  return  of  the 
Express  from  the  city,  rather  than  lose  his  reputation  or  gain 
a  bad  one.  In  many  cases  a  microscope  is  employed  in  very 
refined  focussing,  especially  in  copying. 

Polarization. 

This  trouble  does  not  occur  very  frequently;  it  is  made 
manifest  by  the  redness  which  the  high-lights  are  wont  to 
assume  during  development,  when  the  exposure  has  been 
either  too  long  or  the  light  too  brilliant,  as  in  the  copying 
process  by  the  direct  rays  of  the  sun.  This  evil  can  be 
remedied  by  avoiding  the  causes,  or  by  the  use  of  a  bromo- 
iodized  collodion,  or  of  citric  acid  in  the  developer. 

Tender  and  Rotten  Films. 

These  occur  generally  in  collodion  of  a  certain  make, 
owing  to  the  peculiar  nature  of  the  pyroxyline,  or  the  relative 
quantity  of  alcohol  and  ether.  The  defect  may  arise,  how- 
ever, by  immersing  the  plate  too  quickly  into  the  silver  bath 
before  the  film  has  set ;  also  by  immersing  the  plate  when 
the  film  is  too  dry,  in  which  case  it  cracks  and  splits  up  in 
the  development. 

There  is  no  remedy  for  a  rotten  film ;  but  a  tender  or 
structureless  film  can  be  retained  on  the  glass  by  first  filing 
the  edges  as  recommended,  and  then  by  careful  manipula- 
tions in  the  various  operations  of  developing,  fixing,  and 
washing 


IMPERFECTIONS  AND  THEIR  REMEDIES. 


333 


Imperfections  in  Paper  Prints. 
These  are  to  be  attributed  to  defects  in  the  paper  /  to  im- 
perfect albumenizing  and  salting  ;  to  defective  sensitizing  / 
to  defects  in  the  printing  or  in  the  negative  ;  to  imperfect 
washing  previous  to  toning  /  to  defective  toning  ;  to  defect- 
ive fixing  /  to  stains  of  various  kinds ;  mealiness  on  the 
print. 

Defects  in  the  Paper. 
A  defective  piece  of  paper  must  always  be  rejected  at 
once.  By  regarding  the  paper  by  transmitted  light,  very 
frequently  imperfections  in  the  substance  of  the  material  can 
be  descried,  which  otherwise  would  escape  observation.  Par- 
ticles of  inorganic  matter,  such  as  lime,  the  oxide  of  iron,  etc., 
may  be  found  in  the  substance,  which  in  the  various  stages 
of  the  printing  operation  become  manifest  by  decomposi- 
tion. In  choosing  paper,  where  you  can  make  the  selection, 
examine  each  sheet  separately  for  mechanical  defects  both  of 
structure  and  of  contamination,  and  reject  whatever  is  in 
any  way  defective. 

Imperfect  Albumenizing  and  Salting. 
The  albumenizing  and  salting  require  careful  and  neat 
management.  If  the  albumen  is  not  very  thoroughly  broken 
up,  it  will  assuredly  produce  irregularities  in  the  albumeniz- 
ing. The  salting  materials  must  be  mixed  up  at  the  same 
time  with  the  albumen,  but  after  solution  in  a  small  quantity 
of  water  ;  otherwise  particles  of  the  salt  will  remain  undis- 
solved and  give  a  spotted  appearance  in  the  printing.  Use 
the  albumen  while  fresh.  See  that  the  surface  is  not  com- 
posed of  bubbles  ;  where  these  exist  you  will  have  a  marbled 
or  oolitic  appearance  on  your  print.  If  the  paper  exhibits 
such  minute  bubbles  when  removed  from  the  salting  solu- 
tion, break  these  bubbles  all  up  with  a  clean  feather  or  soft 
sponge,  and  float  the  paper  again  until  the  film  is  uniform. 
The  amount  of  salting  ought  to  bear  a  relation  of  equiva- 
lents with  the  silver  solution  used  subsequently. 

Defective  Sensitizing. 
Filter  the  silver  solution  before  use,  or  at  least  remove  all 
particles  of  dust  or  oxide  from  its  surface,  otherwise  your 
prints  will  be  spotted  and  frequently  covered  with  fortifica- 
tions. A  marbled  appearance  is  caused  by  a  weak  silver  so- 
lution, or  too  short  a  time  of  floating.  It  may  arise  from 
defects  in  the  albumenizing,  as  just  referred  to.  In  quick 
floating  the  solution  must  be  very  strong.    In  some  cases  the 


334 


IMPERFECTIONS  AND  THEIR  REMEDIES. 


solution  seems  to  be  rejected  from  the  surface  of  the  albu- 
men ;  rub  over  the  solution  with  a  tuft  of  cotton ;  float  again, 
and  the  trouble  will  be  overcome. 

Defects  i?i  the  Printing  or  in  the  Negative, 
A  weak  negative  will  inevitably  produce  a  weak  print. 
Weak  prints,  too,  are  the  result  of  too  dilute  a  silver  solu- 
tion. JBronzing  arises  frequently  from  a  want  of  true  rela- 
tion between  the  lights  and  shades  in  the  negative.  An  in- 
tensified ambrotype  used  as  a  negative  will  produce  a  bronzed 
picture.  Thus  under-exposure  and  over-development  are  the 
causes  of  bronzing. 

A  harsh  print  proceeds  also  from  under-exposure  and  over- 
development in  the  negative  ;  there  is  a  want  of  middle-tone — 
the  picture  is  all  black  and  white. 

Many  prints  are  spoiled  in  the  act  of  printing  by  extreme 
carelessness.  Watch  the  operation  ;  the  two  guides  of  suc- 
cess are  :  Print  as  long  as  the  high-lights  are  perfectly  white, 
and  bronzing  has  not  yet  commenced.  The  impression  of  a 
perspiring  finger  on  the  sensitive  film,  as  well  as  many  other 
similar  organic  contaminations,  also  give  rise  to  bronzing. 

Imperfect  Washing  previous  to  Toniyig. 

The  print,  when  removed  from  the  printing-frame,  contains 
nitrate  of  silver  and  nitrate  of  the  alkalies  used  in  the  salt- 
ing solutions,  albuminate  of  silver,  chloride  of  silver ;  the 
latter  salt  has  been  partly  acted  upon  by  light  so  as  to  form 
the  picture,  and  another  part  has  not  been  changed.  The 
nitrates  must  all  be  removed  by  careful  washing  in  several 
waters  before  the  toning  is  commenced,  otherwise  the  toning 
will  be  slow  and  imperfect. 

The  operation  of  washing  must  take  place  soon  after 
printing  and  immediately  before  toning,  in  order  to  secure 
a  good  and  quick  tone. 

Defective  Toning. 

This  imperfection  may  arise  from  contaminations  intro- 
duced into  the  toning  solution  by  imperfectly  washed  prints ; 
the  gold  solution  becomes  thereby  decomposed  and  incapable 
of  toning  the  printed  film.  The  defect  may  arise  from  im- 
pure chloride  of  gold ;  from  an  acid  condition  of  the  toning 
solution  ;  from  bad  paper  ;  from  the  lowness  of  the  temper- 
ature ;  from  an  excess  of  elevation  of  temperature.  The 
imperfections  of  toning  are  : 

A  red  tone  after  fixing ;  this  is  owTing  to  an  insufficiency 
of  toning. 


IMPERFECTIONS  AND  THEIR  REMEDIES. 


335 


A  blue  tone  after  fixing  ;  this  is  owing  to  an  excess  of  ton- 
ing ;  or  to  an  acid  toning  solution. 

A  yellow  tone  in  the  whites  after  fixing ;  this  may  be  ow- 
ing to  imperfect  washing,  imperfect  toning,  imperfect  fixing, 
dirty  fingers,  introduction  of  hyposulphite  of  soda  into  the 
toning  solution,  or  upon  the  prints.  The  defect  in  question 
may  arise  also  from  the  decomposition  of  the  gold  in  pathces, 
for  want  of  uniform  mixture  before  the  prints  are  introduced. 

Defective  Fixing. 
A  dark  mottled  appearance  in  the  body  of  the  paper  in- 
dicates imperfect  fixing  combined  with  the  action  of  the  light 
on  the  unaltered  chloride  during  fixing.  An  exhausted  hy- 
posulphite bath  may  also  give  rise  to  this  defect.  A  bath 
containing  hydrosulphuric  acid,  or  a  free  acid,  which  will  pro- 
duce the  former,  gives  rise  to  this  dark-gray  mottled  defect. 

A  yellow  tone  in  the  ichites  arises  very  frequently  from  sid- 
phurized  hyposulphite  stains  of  various  lands. 

These  are  owing  to  irregular  and  careless  manipulations. 
The  introduction  of  the  fingers  into  the  various  baths,  and 
indiscriminately  from  one  bath  into  another,  is  the  cause  of 
a  number  of  stains  on  the  prints,  as  well  as  of  abnormal  ac- 
tion of  the  baths  themselves. 

Make  rules  for  yourself,  such  as  the  following,  and  observe 
them  minutely : 

1.  Print  just  to  bronzing,  or  until  the  whites  begin  to  be 
affected. 

2.  Wash  soon  after  printing  in  clean  water  and  clean  pails. 

3.  Move  the  prints  about  in  the  washing  ;  repeat  the  wash- 
ing three  times  ;  two  or  three  minutes'  duration  for  each  is 
enough.    Long  washing  is  injurious 

4.  The  chloride  of  gold  must  be  pure ;  the  solution  must 
be  neutralized  with  alkalies  or  lime. 

5.  The  toning  solution  must  be  warm — about  100° — and 
well  mixed — and  clean. 

6.  Wash  after  toning  quickly — in  warm  or  hot  water  pref- 
erable— take  care  to  introduce  no  gold  solution  into  the  fix- 
ing solution,  and  vice-versd. 

7.  Move  the  prints  about  in  all  the  solutions,  so  as  to  avoid 
bubbles  and  uneven  action. 

8.  Tone  to  purple  or  incipient  violet. 

9.  Use  fresh  toning  for  a  fresh  batch  of  prints. 

10.  Add  fresh  hyposulphite  every  time  to  the  old  bath, 
or  use  a  fresh  fixing-bath  every  time ;  let  the  bath  be  warm. 


336 


IMPERFECTIONS  AND  THEIR  REMEDIES. 


1 1 .  Alcohol  is  an  advantage  in  all  the  solutions  beginning 
with  the  nitrate  of  silver  to  the  hyposulphite  of  soda. 

12.  Wash  very  thoroughly  after  fixing. 

Mealiness  on  the  Print. 

Some  authors  speak  of  this  defect  in  albumen  prints.  It 
is  said  to  proceed  from  paper  that  has  been  long  albumen- 
ized,  or  from  the  paper  itself.  The  remedy  is  to  immerse 
the  prints  in  a  solution  of  two  ounces  of  water  and  eighteen 
grains  of  acetate  of  soda,  and  to  keep  them  in  this  liquid 
for  about  ten  minutes. 

Prints  frequently  appear  as  if  covered  with  snow,  but  the 
surface  is  quite  smooth  and  the  whites  clear ;  this  defect  is 
attributable  to  the  negative,  which  has  been  strengthened  by 
pyrogallic  acid  containing  too  much  nitrate  of  silver.  The 
surface  of  the  negative  becomes  thereby  covered  with  a  pul- 
verulent deposit.  There  is  no  remedy  for  such  a  negative ; 
there  is  a  remedy,  however,  to  such  a  mode  of  intensifying. 
In  the  first  place,  the  negative  must  contain  the  middle  tones 
before  you  begin  to  intensify;  secondly,  intensify  slowly, 
which  is  effected  by  adding  only  three  or  four  drops  of  silver 
at  a  time  to  the  pyrogallic  acid,  and  shaking  well  before  use. 


CHAPTER  XLV. 


SWAN'S  NEW  CAEBON  PROCESS — THE  CUPRAMMONIUM  PROCESS. 

Those  who  have  long  practiced  themselves,  or  have  taken 
an  interest  in  the  progress  of  this  wonderful  art,  will  re- 
member the  rude  check  given  to  public  confidence  when 
the  fact  of  the  instability  of  the  prints  became  notorious. 
Dilettanti,  who,  till  that  time,  had  paid  liberally  for  choice 
examples,  were  at  once  deterred  from  furnishing  their 
folios  with  such  evanescent  favorites,  the  loss  of  each  of 
which  was  the  more  lamented  in  proportion  as  its  beauty 
and  completeness  had  been  admired. 

An  art  whose  ultimate  results  stand  in  dubious  estima- 
tion, will  never  draw  into  the  ranks  of  its  professors  those 
whose  artistic  knowledge  would  develop  its  great  capabili- 
ties, and  raise  its  status  from  the  mere  mechanical  process 
— which,  very  unjustly,  has  been  its  designation — to  its 
proper  attribution  as  the  translator  of  the  feeling  and 
thought  of  the  individual  directing  its  powers. 

The  printing  processes,  therefore,  are  of  vital  import- 
ance to  the  future  of  photography,  and  those  who  desire 
its  advancement  should  hail  with  satisfaction  the  an- 
nouncement of  the  perfecting  of  one  which  promises  to  re- 
suscitate the  drooping  interest  in  the  art,  which  the  fading 
of  the  print  had  mainly  originated. 

It  appears  to  the  writer  that  by  carbon  printing  a  result 
so*  desirable  is  attained,  and  that  in  numerous  applications 
of  photography,  such  as  book  illustration,  whether  it  be 
for  historic,  scientific,  pictorial,  or  other  representation,  a 
vast  field  presents  itself  to  its  wondrous  facility  of  rend- 
ering objects  with  a  finish  and  delicacy  with  which  it  is 
hopeless  for  the  burin  of  the  most  accomplished  engraver 
to  compete.  "Whilst  in  those  directions  in  which  it  has 
previously  largely  utilized  the  feeling  induced  by  renewed 
confidence  in  the  complete  permanence  of  the  print,  will 
still  more  increase  the  patronage  already  bestowed  upon  it. 

The  writer  feels,  that  although  carbon  printing  is  the 


338 


swan's  new  carbon  process. 


youngest  and  last,  it  must,  in  description — from  its  valu- 
able qualities — take  precedence  of  its  seniors.  The  fol- 
lowing are  the  practical  details  of  Swan's  Carbon  Process, 
published  in  June,  1868,  and  condensed  by  Lake  Price: 

Sensitizing  the  Carbon  Tissue. 

The  sensitizing  solution  may  consist  of  one  part  of  bi- 
chromate of  potash  and  twelve  parts  of  water.  If  hot 
water  is  used  to  dissolve  the  bichromate,  the  solution  must 
not  be  used  till  quite  cold.  If  the  temperature  of  the  so- 
lution is  much  over  60°,  the  gelatinous  coating  of  the 
tissue  is  apt  to  "  run."  The  solution  may  be  used  in  a  flat 
earthenware  dish,  such  as  is  ordinarily  employed  in  pre- 
paring photographic  paper;  or,  if  for  large  sheets,  the 
trough  may  with  advantage  be  deeper,  and  if  more  con- 
venient, be  made  of  wood,  lined  with  marine  glue.  It  is  a 
great  advantage  to  have  the  trough  considerably  larger 
than  the  sheet,  and  an  abundant  supply  of  the  sensitizing 
solution.  The  sheet  of  tissue  is  best  immersed  with  the 
face  upward.  The  operation  should  begin  by  deeply  im- 
mersing one  edge,  and  then  the  entire  sheet  should  be 
drawn  in  under  the  liquid.  Not  one  air-bubble  need  be 
formed  on  the  face,  but  they  cannot  be  avoided  on  the 
back  (unless  the  back  be  wetted,  before  immersion,  by 
brushing  the  sensitizer  over  it);  therefore,  immediately 
after  immersing  the  sheet,  turn  it  over,  and  brush  the 
bubbles  away;  this  having  been  quickly  and  neatly  done, 
the  sheet  is  again  brought  face  up,  and  is  repeatedly 
drawn  in  under  the  liquid  as  before.  This  manipulation 
must  be  continued  until  the  tissue  acquires  a  certain  de- 
gree of  limpness.  American  clips  are  then  attached,  and 
the  sheet  is  gently  and  slowly  raised  out  of  the  trough,  so 
that  the  liquid  may  drain  off  the  face  of  the  tissue  without 
forming  into  streams.  If  the  sheet  is  large,  it  will  require 
to  be  supported  by  a  thin  slip  of  wood,  placed  along  its 
upper  edge,  and  clipped  to  the  sheet;  or  it  may  be  laid 
(back  down)  on  thin  muslin,  stretched  on  a  frame  placed 
in  a  sloping  position.  The  tissue  generally  requires  to  re- 
main about  two  minutes  in  the  sensitizer,  but  the  condi- 
tion of  the  tissue  as  to  limpness  is  a  better  guide  than 
counting  minutes.  If  taken  out  too  soon,  the  tissue  will 
not  be  very  sensitive :  if  left  in  too  long,  it  will  become  so 
heavy  and  tender  that  it  cannot  be  suspended  by  the  clips. 
The  sensitizing  must,  of  course,  be  done  in  a  dark-room, 


SWANS  NEW  CAEBON  PROCESS. 


339 


and,  as  the  tissue  is  three  times  as  sensitive  as  silvered 
paper,  unusual  care  must  be  taken  not  to  expose  it  to  day- 
light. 

Drying. 

The  place  where  the  tissue  is  put  after  sensitizing  must 
be  dark  and  dry.  It  is  essential  that  the  tissue  should  dry- 
quickly,  yet  the  drying  must  not  be  accelerated  by  heat, 
unless  the  temperature  is  very  low.  There  should  be  a 
good  current  of  air  in  the  room,  and  the  tissue  should  be 
placed  in  the  draft.  A  desiccating  box,  containing  quick- 
lime or  chloride  of  calcium,  may,  in  case  of  need,  be  made 
use  of,  but  with  a  well  ventilated  room  there  is  usually  no 
necessity  for  that.  If  the  tissue  is  made  sensitive  in  the 
evening,  it  must  be  dry  by  next  morning;  if  dry  before 
then  so  much  the  better. 

Exposure. 

The  tissue  must  on  no  account  be  placed  on  a  negative 
while  it  possesses  the  least  tackiness.  If  used  in  that  con- 
dition, there  is  a  risk  of  adhesion  to  the  negative,  and  the 
print  will  be  spotted  with  dark  patches.  Both  these  evils 
are  prevented  by  using  the  tissue  quite  dry,  and  by  having 
the  pressure  in  the  printing-frame  light  and  equable.  Be- 
fore placing  the  tissue  on  the  negative,  it  is  well  to  brush 
a  small  quantity  of  finely  powdered  French  chalk  lightly 
over  the  surface;  this  tests  the  condition  of  the  tissue,  in- 
stantly showing  if  there  is  any  part  unduly  damp,  also 
diminishing  the  tendency  to  the  dark  patches  mentioned. 
There  should,  of  course,  be  the  merest  trace  of  chalk  dust 
left  on  the  tissue  when  it  is  used. 

The  time  of  exposure  may  be  roughly  stated  at  one- 
third  of  the  time  required  for  ordinary  silver  printing  If 
the  tissue  has  not  absorbed  its  full  quota  of  bichromate,  it 
will  be  less  sensitive,  and  will  require  a  much  longer  ex- 
posure than  if  the  tissue  had  been  allowed  to  absorb  more 
of  the  bichromate  solution.  The  printing  is,  as  a  rule, 
best  done  in  diffused  light.  Greater  brilliancy  is  obtained 
by  sun  printing,  but  if  the  latter  is  resorted  to,  great  care 
is  required  to  guard  against  the  adhesion  of  the  tissue  to 
the  negative,  as  a  consequence  of  the  negative  becoming 
warm. 

Coating  with  Caoutchouc. 
After  the  tissue  has  been  taken  from  the  printing-frame, 


340 


swan's  new  carbon  process 


it  must  be  coated  with  solution  of  caoutchouc  in  benzole 
(about  twelve  grains  per  ounce).  This  solution  is  used  in 
a  flat  trough.  The  tissue  is  trailed  over  the  solution,  so 
that  only  the  face  comes  into  contact  with  it;  the  back 
being  kejDt  clean.  After  draining,  the  tissue  is  suspended 
for  an  hour  or  more ;  the  benzole  will  then  have  com- 
pletely evaporated,  and  a  thin  film  of  India-rubber  will  be 
left  on  the  face  of  the  tissue.  The  extreme  edge  of  the 
coated  sheet  must  now  be  cut  off  all  round  with  a  pair  of 
scissors ;  the  strip  cut  off  need  not  be  more  than  one- 
eighth  of  an  inch  wide.  The  tissue  must  not  be  fingered, 
especially  after  coating  with  caoutchouc. 

The  next  step  is  to  lay  the  coated  face  of  the  tissue  down 
upon  a  piece  of  caoutchouc-coated  paper,  the  two  surfaces 
being  brought  into  contact,  so  that  no  air  is  inclosed. 
When  this  is  done,  the  tissue  and  paper  must  be  pressed 
tightly  together  by  means  of  a-  photographic  glazing  or 
copper-plate  printing  press.  Whilst  pressing,  the  tissue 
should  be  laid  on  a  smooth  plate,  a  felt  cloth  being  at  the 
back.  Unless  pretty  heavy  pressure  is  used,  blisters  will 
occur  in  developing. 

Developing. 

After  the  operations  described,  the  tissue  is  immersed  in 
tepid  wrater;  from  80°  to  90°  Fahr.  is  sufficiently  warm. 
After  the  lapse  of  ten  minutes  or  thereabouts,  the  paper 
which  formed  the  backing  of  the  tissue  must  be  removed. 
There  is  no  necessity  to  use  much  force  in  doing  this,  if 
sufficient  time  is  allowed,  and  the  tissue  is  of  the  proper 
degree  of  solubility  (such  as  it  will  be,  if  it  was  quickly 
dried  and  is  fresh),  the  backing  will  come  off  very  easily. 
It  is  not  desirable  to  attempt  to  remove  it  prematurely; 
but  neither  is  it  well  to  leave  the  backing  on  after  it  is 
easily  removable.  When  the  backing  is  removed,  the  de- 
velopment of  the  print  will  proceed  rapidly. 

With  tissue  in  a  good  condition  the  print  will  be  fully 
out  and  clean  in  a  few  minutes  after  uncovering.  Several 
prints  may  be  developed  in  the  same  trough,  but  they  must 
not  be  crowded  together,  nor  allowed  to  chafe  one  on  the 
other.  The  face  of  the  print  should  be  downward  during 
development.  Every  print  must  be  quite  immersed,  and 
no  air  must  be  under  them.  As  each  print  becomes  clean, 
it  should  be  transferred  to  a  trough  of  cold  water,  any  that 
appear  lightly  exposed  being  first  attended  to.  The  prints 
should  remain  immersed  at  least  three  hours,  in  order  that 


swan's  new  carbon  process. 


341 


the  soluble  salts  of  chromium  may  dissolve  out.  Prints 
that  are  fully  developed  at  first,  only  require  a  slight  final 
rinse  in  tepid  water  after  they  have  remained  the  specified 
time  in  the  cold  water  bath.  The  more  deeply  printed  im- 
pressions are  treated  with  warmer  water,  and  are  allowed 
to  remain  in  it  until  they  are  sufficiently  light;  they  are 
then  hung  up  to  dry.  Over-exposed  prints  may  oftert  be 
recovered  by  subjecting  them  to  the  action  of  hot  water 
for  several  hours,  but  very  hot  water  should  never  be  used 
except  in  such  a  case.  The  lower  the  temperature  at  which 
the  development  can  be  effected  the  better.  By  keeping 
the  temperature  of  the  first  developing  bath  as  low  as  pos- 
sible (say  85°),  a  shorter  exposure  suffices,  and  prints  that 
would  have  been  destroyed  by  water  at  100°  are  success- 
fully developed  at  85°. 

Coating  with  Gelatine. 

The  prints,  after  having  become  dry,  or  nearly  so,  are 
flooted  upon  a  solution  of  gelatine  and  glycerine,  consist- 
ing of  one  part  glycerine,  four  parts  of  gelatine,  and  forty 
parts  of  water.  The  solution  should  of  course  be  used  hot, 
and  the  greatest  care  should  be  taken  that  the  coating  is 
uniform,  and  free  from  air-bubbles.  When  the  coating  is 
dry,  the  prints  are  ready  for  the  retransfer  operation.  This 
is  performed  by  placing  the  print,  face  down  upon  a  sheet 
of  wet  paper,  and  passing  it  through  a  copper-plate  press. 
The  paper  is  best  wetted  by  immersion  in  water.  Several 
sheets  (wetted  separately,  and  carefully  freed  from  air) 
may,  whilst  fully  immersed  in  the  water,  be  placed  one  over 
the  other,  and  be  drawn  out  of  the  water  in  a  pack,  and  so 
hung  up  to  drain.  It  is  an  important  point  to  have  the 
paper  evenly  wetted,  and  wet  to  the  proper  degree  when  it 
is  used,  and  also  that  the  gelatinised  surface  of  the  print 
should  not  be  fingered,  or  in  any  way  soiled.  The  paper 
should  not  be  quite  so  wet  that  the  water  stands  out  on 
the  surface,  but  it  should  be  wet  almost  to  that  degree. 
The  print  should  be  laid  on  the  wet  paper,  slightly  rubbed 
into  contact ;  it  then  should  be  quickly  reversed,  and  laid 
on  the  steel  bed  of  the  press;  the  blanket  (of  thick  felt) 
should  then  be  brought  over  the  wet  paper,  and  the  press 
"  pulled  "  with  heavy  pressure  and  a  steady  slow  motion. 
After  pressing,  the  print,  enclosed,  between  two  papers,  is 
passed  through  a  solution  of  alum,  and  is  afterward  rinsed 
in  water;  it  is  then  suspended  to  dry,  and  when  thor- 
oughly so  is  ready  for  the  final  operation,  viz. : 


34:2 


THE  CUPRAMMONIUM  PROCESS. 


Removing  the  Caoutchouc  Paper. 

To  effect  this,  the  paper  is  slightly  moistened  with  ben- 
zole ;  this  so  loosens  the  attachment  of  the  caoutchouc 
paper  to  the  print  that  it  can  be  easily  stripped  off.  The 
paper  should  be  merely  moistened  with  benzole,  and  no 
time  should  be  lost  in  removing  the  paper  after  the  ben- 
zole is  rubbed  in.  Before  attempting  to  remove  the  paper, 
it  is  best  to  commence  the  separation  by  running  the  point 
of  a  blunt  knife  between  print  and  paper,  along  one  side. 
If  the  retransfer  has  been  perfectly  done,  the  attachment 
of  the  print  to  the  paper  will  be  so  strong  that  they  can- 
not be  separated  (unless  wet)  without  the  face  of  the 
paper  tearing.  If  there  are  any  air-bubbles  in  the  gela- 
tinous coating,  or  if  the  coating  has  been  soiled  by  finger- 
ing, there  will  of  course  be  a  want  of  adhesion  of  the  print 
at  such  places,  and  those  points  of  the  print  will  tear  up  in 
the  act  of  removing  the  caoutchouc  paper.  The  caout- 
chouc paper  adheres  to  the  print  with  such  tenacity  as 
thoroughly  to  test  the  adhesion  of  the  print  to  its  final 
basis. 

For  further  details  on  the  process  of  Carbon  Printing, 
the  reader  is  referred  to  a  work  on  the  same  subject  by 
Mr.  A.  J.  Drummond,  issued  by  our  publisher. 

Monckhoven's  Cuprammonium  Process. 

Mr.  Schweitzer's  discovery,  that  the  cuprate  of  ammonia 
readily  dissolves  the  fibers  of  cotton,  has  caused  me  to  re- 
flect whether  this  circumstance  could  not  be  applied  ad- 
vantageously to  the  photographic  process.  I  have  suc- 
ceeded, after  numerous  experiments,  in  discovering  a  ready 
and  not  very  costly  method. 

The  simplest  and  most  convenient  way  seemed  to  be,  to 
dissolve  in  a  solution  of  cotton,  in  the  before-mentioned 
copper  salt,  newly  precipitated  oxide  of  silver,  to  spread 
the  solution  on  a  glass  plate,  to  dry  the  stratum  on  the 
same,  and  let  it  pass  through  diluted  hydroiodic  or  hydro- 
bromic  acid.  In  this  way  a  white  stratum  of  iodide  or 
bromide  of  silver  is  obtained,  but  I  was  never  successful 
in  getting  a  clear  and  transparent  picture.  A  continuous 
layer  of  reduced  silver  always  forms  below  the  stratum  of 
cotton,  and  the  picture  on  the  surface  is  lost.  I  applied, 
without  effect,  simple  bromide  of  cuprate  of  ammonia,  or 
simple  iodide  of  cuprate  of  ammonia;  invariably  a  brown 


THE  CUPRAMMONIUM  PROCESS. 


343 


stratum  of  metallic  silver  formed  below  the  picture.  I 
mention  this  fact  to  prevent  others  from  making  useless 
experiments.  I  was  perfectly  successful  by  adopting  the 
following  plan :  To  prepare  the  solution  of  cuprate  of  am- 
monia, a  concentrated  solution  of  sal  ammoniac  is  satu- 
rated with  newly-precipitated  oxide  of  copper;  or  Peligot's 
method  may  be  employed,  which  I  recommend  to  photo- 
graphers as  being  very  easy  to  perform. 

As  soon  as  the  solid  impurities  have  settled  in  this  solu- 
tion, perfectly  white  cotton  is  dissolved  in  the  same  in  the 
proportion  of  ten  grammes  to  the  litre.  In  this  way  a  thick 
liquid  is  obtained  which  must  be  diluted  with  some  water, 
so  that  the  cotton  is  entirely  dissolved.  This  liquid  is 
mixed  with  a  concentrated  solution  of  iodide  of  potash,  so 
that  one  litre  of  the  solution  contains  from  five  to  ten 
grammes  of  iodide  of  potassium.  The  liquid  thus  obtained, 
which  may  be  preserved  for  an  indefinite  period,  is  spread 
on  the  glass  plates.  The  beauty  of  the  picture  depends 
entirely  on  the  correct  preparation  of  the  solution  of  cotton 
in  the  cuprate  of  ammonia.  This  solution  should  be  thick, 
so  as  to  spread  slowly  on  the  plate,  and  when  dry  the 
stratum  should  be  perfectly  transparent,  and  void  of  any 
dull  appearance.  If  the  solution  be  too  thin,  the  picture 
is  only  superficial,  and  it  can  be  obliterated  with  a  stream 
of  water.  When  the  solution  of  cotton  has  been  thus 
poured  upon  the  glass  plate,  it  spreads  over  it  readily,  and, 
as  it  evaporates  slowly,  the  liquid  (with  the  end  of  a 
glass  tube)  can  be  brought  to  flow  to  those  spots  which, 
from  the  first,  may  have  remained  uncovered.  The  sur- 
plus liquid  is  made  to  drain  off,  and  the  plate  is  put  per- 
pendicular against  the  wall.  There  are  two  different  ways 
to  proceed  further:  The  plate  is  allowed  to  evaporate  only 
for  a  few  minutes;  the  surplus  liquid  collects  at  the  lower 
edge  and  is  removed  by  means  of  a  piece  of  silk  tissue 
paper,  and  the  plate  is  now  immersed  in  a  newly  prepared 
bath  of  nitrate  of  silver  which  is  diluted  with  acetic  acid 
and  with  acetate  of  silver.  The  stratum  becomes  white,  as 
with  the  usual  mode  of  proceeding,  by  means  of  the  iodide 
of  silver  formed;  the  plate  is  then  exposed  in  the  camera, 
and  the  picture  fixed  in  the  ordinary  manner.  2d.  Should 
the  glass  be  allowed  to  dry  entirely,  the  ammonia  is  ex- 
pelled by  evaporation,  and  the  ordinary  reaction  of  the  io- 
dide of  potassium  on  the  copper  salts  takes  place,  and 
half  iodide  of  copper  is  formed  in  the  interior  of  the  stra- 
tum of  cotton,  and  iodine  itself  on  its  surface.    Such  a 


344 


THE  CUPEAMMONIUM  PROCESS. 


covering  of  the  glass  has  a  red  appearance  when  dry,  and, 
if  immersed  in  the  nitrate  of  silver,  a  superficial  picture  is 
formed  which  is  removed  by  the  slightest  washing,  and, 
also,  on  account  of  the  half  iodide  of  copper,  metallic  silver 
is  formed  below  the  picture. 

I  overcame  these  difficulties  by  immersing  the  glass 
plate  in  pure  alcohol,  free  of  water,  and  saturated  with  a 
stream  of  dry  gas  of  ammonia.  The  free  iodine  is  trans- 
formed into  iodide  of  ammonium,  and  aldehyde  is  formed. 
An  immersion  of  a  few  seconds  is  sufficient  to  render  the 
glass  white.  When  the  glass  is  taken  from  this  bath,  it  is 
moved  in  the  air,  in  order  to  remove  the  surplus  ammonia 
by  evaporation,  and  it  is  now,  while  still  quite  wet,  im- 
mersed in  the  nitrate  of  silver,  and  the  rest  of  the  opera- 
tion is  as  usual.  Very  fine  and  extremely  transparent  pic- 
tures can  be  obtained  by  this  process,  and  for  this  reason  it 
is  peculiarly  adapted  for  taking  buildings  and  landscapes. 
It  is  clear  that  simple  cotton  will  supersede,  in  future,  the 
gun-cotton  or  collodion  in  photographs;  the  preparation 
of  the  latter  for  this  purpose  being  always  attended  with 
some  difficulties. 


CHAPTER  XLVL 


IMPROVED   TANNIN   PROCESS — THE   ALKALINE  DEVELOPER  

TANNIN  AS  A  SENSITIZER — CHROMO-PHOTOGRAPHY — PRO- 
CESS WITHOUT  THE  SALTS  OF  SILVER — CELESTIAL  PHO- 
TOGRAPHY. 

Since  the  manuscript  of  the  "Sunbeam"  was  submitted  to 
the  Publishers,  important  additions  have  been  made  to  our 
knowledge  of  actinic  action  on  chemical  substances.  It  is 
proposed,  therefore,  not  to  make  any  changes  in  the  original 
text  of  the  work,  but  to  append  the  new  discoveries  as  a 
supplementary  part. 

The  first  important  change  refers  to  the  totally  different 
mode  of  developing  Tannin  plates  from  that  which  has  hith- 
erto been  practiced.  The  acid  developer  yields  up  its  ca- 
reer to  an  alkaline  developer  ;  and  so  superior  and  satisfac- 
tory are  the  results  of  the  latter  when  compared  with  the 
former,  that  from  personal  experience  it  is  asserted  that 
there  is  now  no  prospect  of  a  retrograde  motion.  The  al- 
kaline mode  of  developing  tannin-plates  (and  probably 
also  all  other  dry  plates)  is  bound  to  effect  a  complete 
revolution  in  photographic  manipulations.  An  attempt  to 
theorize  upon  the  action  of  the  new  developer  would  be 
altogether  premature  ;  for  facts,  accumulated  observations 
must  first  be  made  and  accurately  studied  before  any  gen- 
eralizations can  be  constructed  in  the  formation  of  a  theory. 
The  scientific  photographer  is  even  not  yet  prepared  to  as- 
sign any  reliable  rationale  of  the  principles  of  actinism  on 
metallic  salts ;  how,  then,  is  it  possible  to  elevate  a  perma- 
nent edifice  on  an  unknown  foundation  ?  It  would  be  equiv- 
alent to  constructing  the  roof  of  a  house  midway  between 
heaven  and  earth  without  any  beams  to  support  it.  Various 
attempts  have  been  ingeniously  made  to  account  for  the  pe- 
culiar action  of  light  on  chemical  materials  ;  but  the  learned 
authors  of  the  different  views  promulgated  still  differ  widely 
in  their  conclusions  ;  and  as  yet,  no  Kepler  and  no  Newton 
has  arisen  above  the  horizon  to  dissipate  their  conflictions 
by  a  single  unique  and  satisfactory  rational  analysis. 

Tannin  Process  with  the  Alkaline  Developer. 
The  author  has  had  experience  in  manipulations  with 
tannin-plates,  and  thinks  he  has  acquired  success.    Let  it 


846 


IMPROVED  TANNIN  PROCESS. 


be  understood,  therefore,  that  the  information  here  com- 
municated is  not  intended  to  exclude  other  ways  and  means 
of  effecting  the  same  ends,  (some  of  which  may  even  be 
superior,)  but  simply  to  lay  before  the  reader  a  reliable 
process  in  detail,  which  will  certainly  produce  satisfaction, 
if  the  rules  are  carefully  and  minutely  followed. 

Collodion. 

Any  good  bromo-iodized  collodion  is  suitable  for  the  pre- 
paration of  tannin-plates.  That  which  is  sold  by  our  re- 
spectable dealers  produces  excellent  results.  The  following 
will  be  found  a  good  formula  : 

Formula  for  Collodion. 


Ether,  (concentrated,)   20  ounces. 

Alcohol,   15  " 

Iodide  of  ammonium,   80  grains. 

Iodide  of  cadmium,   80  " 

Bromide  of  cadmium,   40  " 

Pyroxyline,   180  " 

Iodine,   2  " 


Previous  to  coating  the  plates  with  collodion,  it  is  advis- 
able to  coat  them  with  a  solution  of  bromo-iodized  gelatine, 
as  recommended  by  Major  Russell.  This  solution  is  pre- 
pared as  follows  : 

"  Soak  twenty  grains  of  pure  gelatine  (such  as  is  prepared 
for  culinary  purposes)  in  eight  ounces  of  distilled  water 
and  four  drops  of  glacial  acetic  acid.  When  thoroughly 
swelled  and  transparent,  dissolve  by  warming.  Dissolve 
three  grains  of  iodide  of  cadmium,  three  grains  of  bromide 
of  cadmium,  and  a  grain  of  iodine  in  a  few  drops  of  water, 
and  mix  with  the  solution ;  then  filter  two  or  three  times 
through  white  filtering  paper  in  a  warm  place.  The  acetic 
acid  coagulates  the  white  impurity,  which  then  collects  into 
filaments,  and  is  removed  by  filtering,  leaving  the  liquid 
very  bright. 

"  This  solution  will  keep  well  without  alcohol,  and  it  is 
better  not  to  add  it,  as  it  tends  to  produce  ridges  in  the  film 
of  gelatine,  especially  when  present  in  large  proportion." 

This  solution  is  poured  upon  the  plates  in  the  same  man- 
ner as  collodion.  If  the  temperature  is  low,  the  fluid  gela- 
tinizes, and  invariably  produces  an  infinite  number  of  air 
vesicles  ;  this  trouble  can  be  avoided  by  keeping  the  solution 
at  a  temperature  of  about  100°,  and  by  flowing  the  plates 
several  times  in  succession  until  each  bubble  has  disappear- 
ed.   The  plates  are  then  allowed  to  drain,  and  reared  away 


IMPROVED  TANNIN  PROCESS. 


347 


to  drain,  each  glass  standing  on  one  angle,  supported  by  a 
piece  of  glass  covered  with  blotting-paper.  When  the 
plates  are  thoroughly  dry,  each  one  is  passed  over  the  flame 
of  an  alcohol  or  gas-lamp,  gelatine  side  upward,  in  order 
to  dissipate  a  certain  quantity  of  what  may  be  termed  con- 
stitutional moisture ;  when  cool  it  is  ready  to  receive  the 
film  of  collodion. 

The  plate  is  then  sensitized  in  the  nitrate  of  silver  bath. 
For  this  purpose  the  author  generally  uses  a  horizontal  dish 
in  which  two  or  three  plates  can  be  sensitizing  at  the  same 
time.  The  film  must  become  thoroughly  of  a  cream  color 
before  it  is  taken  out.  Without  doubt,  much  of  the  success 
of  the  operation  depends  upon  the  condition  of  the  bath. 
A  successful  silver  solution  is  formed  in  the  following  man- 
ner : 

Nitrate  of  Silver  Bath  for  Tannin  Plates. 

Re-crystallized  nitrate  of  silver,    ....      2  ounces. 

Distilled  water,  24  " 

Oxide  of  silver,  4  grains. 

Iodide  of  silver,  4  " 

Boil  these  ingredients  in  a  glass  retort  for  ten  minutes  or  a 
quarter  of  an  hour,  and  then  set  it  aside  to  cool.  It  is  next 
filtered  through  clean  filtering-paper,  or  the  clear  part,  after 
subsidence,  is  decanted.  The  sediment  can  be  used  in  the 
preparation  of  the  next  bath.  By  this  means  the  solution 
has  been  neutralized  and  iodized  at  the  same  time  ;  and  if 
the  materials  were  all  pure  of  their  kind,  the  bath  contains 
no  impurities  of  any  kind.  In  this  bath  the  collodionized 
plates  are  immersed  and  retained  there  much  longer  than 
for  the  ordinary  wet  collodion  process,  that  is,  until  the  film 
is  decidedly  of  a  cream-like  appearance.  It  is  always  ad- 
visable to  try  a  single  plate  in  a  new  bath  before  proceeding 
to  the  preparation  of  a  large  quantity.  The  object  of  the 
trial  is  to  ascertain  whether  there  is  any  tendency  in  the 
bath  to  produce  fogging.  Should  there  be  any  signs  of  this 
trouble,  which,  with  a  bath  so  carefully  prepared,  is  scarce- 
ly to  be  feared,  add  a  drop  or  two  of  tincture  of  bromine, 
which  acts  in  the  same  way  as  tincture  of  iodine,  by  pro- 
ducing a  decomposition  whereby  the  bath  becomes  slightly 
acid.  The  same  end  may  be  attained  by  adding  the  tincture 
to  the  collodion. 

As  soon  as  the  film  is  in  a  right  condition,  has  been  uni- 
formly whitened,  and  all  oily  appearance  has  disappeared, 
take  the  plates  out  and  rear  them  up  in  the  inside  of  a  pail 
of  w^ater,  slightly  inclined  and  with  the  film  side  downward. 
In  this  position  the  nitrate  of  silver  solution,  by  reason  of 


348 


IMPROVED  TANNIN  PROCESS. 


its  specific  gravity,  will  sink  in  the  water.  Have  three  pails 
side  by  side,  each  nearly  full  of  rain-water.  As  soon  as  a 
second  plate  is  ready,  take  hold  of  the  first  plate,  in  a  hori- 
zontal position,  collodion  side  downward,  give  it  a  sort  of 
modulatory  motion,  but  very  gently,  and  then  transfer  it  to 
the  second  pail,  and  place  it  against  the  side  of  the  latter 
in  an  inclined  position  as  before.  The  second  plate  is  now 
removed  from  the  bath,  and  after  draining,  is  put  in  the 
first  pail.  The  process  is  the  same  when  the  third  plate  is 
ready ;  the  first,  being  treated  as  before,  is  removed  to  the 
last  pail,  the  second  plate  is  immersed  in  the  middle  pail, 
whilst  the  first  pail  becomes  again  empty  for  the  reception 
of  the  next  plate. 

Finally,  the  first  plate  is  flowed  several  times  with  fresh 
distilled  water,  which  thus  removes  every  trace  of  free  ni- 
trate of  silver,  as  well  as  of  the  nitrates  of  the  metals,  pro- 
duced by  decomposition. 

Flowing  the  Plates  with  Tannin. 
The  plates,  thus  thoroughly  and  carefully  washed,  are 
flowed  with  the  following  solution : 


Dissolve  over  night,  and  then  filter  through  a  wet  filter 
two  or  three  times  ;  finally,  add  one  drachm  of  alcohol  if 
the  tannin  has  to  be  kept  some  time. 

Flow  the  plate  with  this  solution,  and  allow  the  super- 
fluous quantity  to  pass  off  at  one  corner  into  a  wide-mouthed 
vial.  Now  flow  the  plate  several  times,  and  collect  the 
residual  quantity  in  the  stock-bottle.  Drain  and  rear  on 
one  corner  on  a  piece  of  glass  covered  with  bibulous  paper. 

Some  photographers  wash  the  tannin  film  before  drying  ; 
we  have  not  tested  this  plan  sufficiently  to  pronounce  an 
opinion  about  it ;  but  prefer  adherence  to  a  mode  which 
invariably  is  successful. 

The  room  in  which  the  plates  are  thus  prepared  may  be 
maintained  moderately  warm,  so  that  the  film  may  dry 
spontaneously,  and  not  very  slowly.  After  each  plate  has 
stood  for  ten  minutes  or  longer,  there  will  be  an  accumula- 
tion of  tannin  solution  on  the  blotting-paper.  It  is  now 
well  to  remove  the  plates  to  fresh  blotting-paper,  and  to 
prepare  the  wet  supports,  with  fresh  pieces  of  blotting- 
paper,  for  other  plates.    If  this  precaution  be  not  observed, 


Formula  for  Tannin  Solution. 


Tannin,     .  . 
Loaf  sugar, 
Distilled  water, 


1  drachm. 
1  " 
4  ounces. 


IMPROVED  TANNIN  PROCESS. 


349 


streaks  and  stains  are  apt  to  manifest  themselves  on  the 
pendent  corner  when  the  film  is  submitted  to  the  develop- 
ing solution.  w 

When  thoroughly  dry,  the  tannin-plates  are  now  ready 
for  exposure,  or  for  piling  away  in  their  proper  receptacle, 
the  dry-box  plate-holder,  or  a  dark  cupboard. 

Exposure  of  Tannin  Plates. 

The  time  of  exposure  naturally  depends  upon  a  variety  of 
contingencies,  such  as  the  intensity  of  light,  the  time  of  the 
day,  the  season  of  the  year,  the  climate,  and  the  power  and 
working  properties  of  the  lens.  With  one  of  Harrison  and 
Sclmitzer's  globe-lenses,  stereoscopic  size,  and  smallest 
aperture, 'in  the  month  of  April,  in  the  State  of  New-York, 
an  exposure  of  from  eight  to  twelve  seconds  will  produce  a 
very  satisfactory  negative.  In  December  and  January, 
during  the  extreme  cold  weather,  from  thirty  to  forty-five 
seconds  were  found  necessary.  Where  the  circumstances 
permit,  it  is  well  to  give  at  least  a  sufficient  exposure,  and 
even  a  little  too  much  is  no  injury,  because  the  development 
is  quite  under  control ;  for  where  the  exposure  has  not  been 
sufficiently  long,  a  picture  can  be  obtained,  it  is  true,  but  it 
is  too  harsh,  it  is  all  black  and  white ;  there  are  none  of 
those  intermediate  or  middle  tints  that  characterize  a  true 
artistic  picture. 

Development  of  Tannin  Plates. 

This  is  the  treatment  which  deviates  entirely  from  what 
has  hitherto  been  practiced.  After  exposure,  the  plates  are 
returned  to  their  dark  receptacles,  in  which  they  remain 
until  required  for  development.  We  are  not  prepared  to 
say  how  long  the  time  may  be  between  exposure  and  de- 
velopment without  being  in  any  way  prejudicial  to  the  latter 
operation.  This  time  is  somewhat  indefinite,  as  long  as  the 
film  is  preserved  in  an  obscure  place,  and  free  from  moisture 
and  deleterious  effluvia. 

The  plate  for  development  is  first  carefully  moistened 
with  distilled  water,  slightly  warmed  in  winter,  that  is,  of  a 
temperature  of  about  60°.  The  film  is  then  covered  with 
the  following  solution  : 

Alkaline  Developer  for  Tannin  Plates. 

Saturated  solution  of  carbonate  of  soda,     ....    30  minims. 

Water,  4  drachms. 

Alcoholic  sol.  of  pyrogallic  acid,  (10  gr.  to  the  oz.,)  .     6  minims. 

The  saturated  solution  of  carbonate  of  soda  is  prepared 
in  the  following  manner  :  To  four  ounces  of  water  add  car 


350 


IMPROVED  TANNIN  PROCESS. 


bonate  of  soda  as  long  as  it  is  dissolved ;  finally  leave  a 
quantity  in  the  bottle  for  a  day  or  longer,  and  shake  the 
mixture  occasionally.    Finally  filter  and  preserve. 

The  solution  of  pyrogallic  acid  is  also  kept  in  stock,  and 
made  by  dissolving  twenty  grains  of  the  acid  in  two  ounces 
of  alcohol. 

Mix  quickly,  and  immediately  pour  it  upon  the  moistened 
plate.  If  the  time  of  exposure  has  been  nearly  right,  the 
image  will  soon  begin  to  appear,  and  although  faint  and  of 
a  slightly  reddish  hue,  will  proceed  until  all  the  parts  have 
appeared.  Do  not  be  alarmed  about  the  faintness  of  the 
picture  ;  as  long  as  all  the  traits  are  distinct,  the  negative 
will  afterward  come  out  quite  right.  Wash  the  film  care- 
fully, and  then  proceed  to  the  next  step. 

Intensifying  of  the  Image  in  the  Tannin  Process, 
Prepare,  in  the  first  place,  the  following  solutions  in  stock- 
bottles  : 

No.  1  Stock-Bottle. 

Pyrogallic  acid,  18  grains. 

Acetic  acid,  1  ounce. 

No.  2  Stock-Bottle. 

Nitrate  of  silver,  40  grains. 

Distilled  water,  2  ounces. 

From  No.  1  take  one  drachm,  and  add  seven  drachms  of 
water.  This  solution  is  for  present  use.  According  to  the 
size  of  the  plate,  pour  a  sufficient  quantity  of  this  solution 
into  a  small  wide-mouthed  vial,  flow  the  film  with  this  so- 
lution, and  then  pour  it  back  again  into  the  vial.  Now  add, 
for  a  stereoscopic  plate,  about  six  drops  of  the  nitrate  of 
silver  solution  from  stock-bottle  No.  2,  shake  the  mixture, 
and  again  pour  it  upon  the  film.  The  traits  will  soon  dark- 
en, and  the  image  finally  will  reach  an  intensity  adapted  for 
the  printing  process.  It  sometimes  happens,  however,  when 
the  exposure  has  been  too  long,  or  from  other  causes,  that 
the  image  begins  to  be  obscured  by  an  incipient  fogging  ; 
when  this  evil  manifests  itself,  throw  off  the  intensifier, 
wash  the  plate  thoroughly,  and  fix  in  the  ordinary  fixing 
solution  of  hyposulphite  of  soda.  The  image  is  again 
washed,  and  the  intensifying  process  can  now  be  prolonged 
until  the  desired  effect  is  obtained. 

If  we  had  used  the  old  acid  developer  with  the  time  of 
exposure  indicated,  it  would  in  most  cases  fail  to  bring  out 
a  negative  image.  The  alkaline  developer  will  be  put  to 
the  test  the  coming  summer ;  we  shall  then  know  positively 


THE   ALKALINE  DEVELOPEK. 


351 


whether  instantaneous  photographs  can  be  taken  by  the 
dry  process. 

Wet  Collodion  Pkocess  with  the  Alkaline  Developer. 

The  author  has  not  yet  had  time  to  test  the  merits  of  this 
process,  which  is  recommended  by  very  high  authority,  the 
editor  of  the  Photographic  Notes.  He  asserts  that  a  nega- 
tive can  be  produced  by  means  of  the  alkaline  developer  in 
about  the  same  time  as  is  generally  given  for  an  ambrotype, 
within  doors  of  course.  As  far  as  our  experience  goes  in 
these  matters  we  should  be  inclined  to  doubt  the  practica- 
bility of  this  process  with  an  ordinary  acid  silver  bath,  that 
is,  the  successful  practicability ;  and  we  would  recommend 
all  photographic  artists  that  feel  inclined  to  try  this  new 
process,  to  prepare  a  neutral  bath  of  pure  ingredients  accord- 
ing to  the  formula  in  the  preceding  article.  In  addition  to 
the  instructions,  set  forth  for  the  first  time  in  the  journal 
just  alluded  to,  it  seems  to  us  to  be  necessary  to  prepare  the 
plates  previously  with  a  coating  of  gelatine,  albumen,  or 
some  other  transparent  medium,  on  which  the  collodion  film 
is  afterward  superposed,  and  by  which  this  film  is  prevented 
from  peeling  off  in  the  subsequent  treatment  of  development 
and  fixing.  In  this  case  the  plates  are  first  well  cleaned 
and  then  coated  with  a  film  of  bromo-iodized  gelatine,  as 
recommended  in  the  preceding  process  for  the  preparation 
of  dry  plates.  This  work  can  be  performed  in  the  evening, 
or  at  times  when  there  is  no  hurry  of  business. 

A  good  bromo-iodized  collodion  is  requisite  for  this  pro- 
cess. First  drive  off  the  moisture  from  each  plate,  already 
gelatinized,  allow  it  to  cool,  and  then  flow  with  the  collodion 
in  the  usual  manner,  and  sensitize  to  a  distinct  cream  color. 
The  plate  is  then  subjected  to  washing,  as  in  the  dry-plate 
process,  and  left  in  a  grooved  box  filled  with  distilled  water 
till  required  for  use.  In  this  way  a  stock  of  plates  is  pre- 
pared early  in  the  morning,  and  put  aAvay  in  water  for  use 
during  the  day. 

When  a  customer  arrives,  the  necessary  position  is  as- 
sumed in  focus,  and  a  plate  is  then  taken  out  of  its  groove, 
flowed  with  distilled  water,  and  then  with  the  following 
solution  : 

Distilled  water,  .   2  ounces. 

Tannin,  30  grains. 

The  solution  is  first  filtered  through  wet  filtering  paper 
two  or  three  times,  and  then  poured  upon  the  collodion  film 
backward  and  forward,  as  is  the  common  practice  with 


352 


THE  ALKALINE  DEVELOPER. 


dry  plates.  The  plate  is  then  allowed  to  drain  for  a  mo- 
ment, and  finally  fixed  in  the  plate-holder.  The  ntmost 
precaution  is  required  here  to  keep  the  corners  of  the  shield 
perfectly  free  from  nitrate  of  silver,  which,  if  present,  will 
inevitably  stain  the  plate  to  a  large  extent  all  along  from 
each  corner  by  a  sort  of  capillary  attraction. 

Exposure, 

The  time  of  exposure  for  a  negative  beneath  a  good  sky- 
light, Sutton  says,  will  be  about  as  long  as  is  required  for  a 
glass  positive.  This  time  varies  according  to  a  variety  of 
circumstances,  which  the  practitioner  has  to  learn  by  ex- 
perience. After  exposure  the  plate  is  taken  into  the  dark- 
room and  flowed  with  distilled  water  ;  if  is  next  submitted 
to  the  developing  process. 

Alkaline  Developer  for  Wet  JPlates. 

To  four  ounces  of  water  add  forty  grains  of  carbonate  of 
soda,  shake  frequently,  and,  after  a  number  of  hours,  filter 
the  solution  through  paper  into  stock-bottle  No.  1. 

Secondly,  dissolve  twenty  grains  of  pyrogallic  acid  in 
two  ounces  of  alcohol,  filter  and  preserve  in  stock-bottle 
No.  2. 

Whenever  an  image  has  to  be  developed,  prepare  each 
time  a  fresh  developer  as  follows,  (for  a  card-picture :) 

Water,  4  drachms. 

Soda  solution,  from  No.  1,  30  minims. 

Pyrogallic  solution,  from  No.  2,    .     .     .    15  minims. 

Shake  quickly  and  then  cover  the  exposed  collodion  film 
with  the  mixture.  If  the  time  of  exposure  has  been  some- 
what near  right,  the  image  will  soon  begin  to  appear  ;  the 
latter  has  a  faint  reddish  color,  if  the  conditions  are  correct. 
As  soon  as  all  the  traits  of  the  picture  are  out,  although 
still  quite  faint,  the  development  may  be  regarded  as  com- 
plete. It  is  of  no  great  consequence,  however,  if  the 
developer  be  left  upon  the  film  for  an  indefinite  time ;  no 
injury  is  thereby  produced,  so  that,  as  regards  this  part  of 
the  business,  when  the  proper  time  of  exposure  is  once 
known,  the  plates  can  be  left  in  the  developer  and  other 
business  in  the  mean  while  attended  to. 

The  next  part  of  the  process  consists  in  strengthening 
and  darkening  the  traits  of  the  image  already  visible.  This 
is  denoininated  the 

Intensifying  of  the  Image, 


TANNIN  AS  A  SENSITIZER. 


353 


Tannin  regarded  as  a  Sensitizer. 

We  are  indebted  to  Poitevin  for  a  very  important  dis- 
covery, which  seems  to  show  that  tannin,  as  well  as  some 
other  bodies  which  we  have  been  in  the  habit  of  regarding 
as  preservatives,  is  in  some  respects  more  appropriately 
designated  a  sensitizer. 

According  to  this  indefatigable  experimentalist  we  have 
the  following  collocation  of  facts  in  reference  to  the  action 
of  light  on  iodide  of  silver : 

1st.  "It  is  not  visible  at  all  on  the  iodide,  which  is  chem- 
ically pure  and  isolated  from  every  substance  capable  of  re- 
taining iodine  which  light  tends  to  decompose. 

2d.  "It  modifies  the  iodide  when  metallic  silver,  nitrate  of 
silver,  and  other  soluble  salts  of  this  metal  are  present,  and 
communicates  to  it  the  property  of  reducing  acid  solutions 
of  silver  by  the  known  developers,  such  as  the  sulphate  of 
protoxide  of  iron,  gallic  or  pyrogallic  acid,  and  even  by  the 
vapor  of  mercury ;  this  is  the  action  made  use  of  in  order 
to  obtain  ambrotypes  or  negatives  in  the  camera. 

3d.  "This  action  reduces  it  to  the  state  of  inert  iodide  on 
developers,  when  under  the  influence  of  light  it  has  been 
covered  with  a  solution  of  an  alkaline  iodide.  This  action 
is  the  same  in  respect  to  metallic  silver,  a  circumstance  giv- 
ing rise  to  the  belief  that  sensitized  iodide  of  silver  is  par- 
tially reduced  to  the  metallic  state,  or,  at  least,  that  itt  has 
lost  a  certain  quantity  of  iodine,  giving  rise  to  a  sub- 
iodide." 

The  author  furthermore  remarks  that  the  chlorides, 
bromides,  etc.,  of  silver  may  be  comprehended  in  the  same 
category. 

Starting  with  this  idea,  that  is,  first  reducing  the  iodide 
of  silver  to  the  inert  condition,  to  that  condition  in  which 
the  ordinary  developers,  after  the  requisite  exposure,  have 
no  power  of  eliciting  any  image,  he  entered  upon  a  course 
of  experiments  in  order  to  ascertain  what  substances  would 
again  communicate  to  the  inert  iodide  its  pristine  sensitive- 
ness. Of  course  the  slightest  quantity  of  a  soluble  salt  of 
silver,  as  of  the  nitrate,  when  flowed  upon  the  film,  would 
be  adequate  for  this  purpose,  as  the  author  well  knew.  But 
the  acids,  gums,  resins,  albumen,  gelatine,  sugars,  spirit  of 
turpentine,  and  many  others,  failed  entirely  to  institute  in 
the  inert  film  a  condition  sensitive  to  the  actinic  influence. 
Most  of  these  substances  are  regarded  as  preservatives,  that 
is,  substances  which  are  supposed  to  preserve  in  the  washed 


354 


TANNIN  AS  A  SENSITIZER. 


sensitized  collodion  films  their  sensitiveness  for  a  given  or 
an  indefinite  time.  Continuing  his  experiments  in  this 
direction,  he  fell  upon  the  discovery  which  forms  in  reality 
the  subject  of  this  article ;  he  found  that  tannin  communi- 
cates to  the  washed  film  of  sensitized  collodion,  or  properly 
speaking  to  the  inert  iodide,  a  sensitiveness  on  exposure 
equal  and  similar  to  that  produced  by  a  solution  of  nitrate 
of  silver. 

"  Tannin,"  says  Poitevin,  "  is  then  a  sensitizer,  and  must 
be  considered  as  such,  and  not  as  a  preserver,  as  all  substances 
are  denominated  that  are  employed  to  preserve  the  sensitive- 
ness of  the  plate,  or  rather  to  prevent  them  from  being  com- 
pletely fogged  in  the  presence  of  reducing  agents  as  soon 
as  the  development  of  the  negative  commences." 

With  this  knowledge  of  the  properties  of  tannin,  a  method 
has  been  devised  of  preparing  sensitive  collodion  films  in  a 
very  different  manner  from  that  hitherto  practiced,  and  by 
means  of  which  many  evils  and  difficulties  can  be  obviated; 
for  these  generally  proceed  from  the  iodide  of  silver  which 
has  not  been  thoroughly  washed  or  prepared  with  extreme 
cleanliness.  The  following  is  the  method  recommended  by 
the  discoverer  : 

" 1  prepare  the  collodion  in  the  usual  manner,  compre- 
hending one  grain  and  one  half  of  the  iodide  to  one  hundred 
grains  of  the  collodion  ;  with  this  I  float  the  plate,  which  is 
afterward  immersed  in  a  bath  of  nitrate  of  silver,  contain- 
ing from  thirty-five  to  forty  grains  of  the  silver  salt  to  the 
ounce  of  water.  I  then  wash  the  film  of  iodide  of  silver 
thus  formed  in  common  water,  in  order  to  remove  the  excess 
of  nitrate  which  covers  it ;  and,  a  circumstance  which  will 
surprise  some  operators,  it  is  not  necessary  to  perform  this 
operation  in  the  dark-room.  The  plate,  having  been  care- 
fully washed,  is  flowed  with  a  solution  of  iodide  of  potas- 
sium, containing  about  eighteen  grains  of  the  iodide  to  one 
ounce  of  water,  the  solution  having  been  previously  satur- 
ated with  iodide  of  silver  by  the  addition  of  a  few  drops  of 
nitrate  of  silver  in  the  bottle  which  contains  it.  This  solu- 
tion of  iodide  of  potassium,  by  the  by,  may  be  used,  until 
exhausted ;  and  it  is  not  necessary  to  use  it  as  a  bath,  but 
simply  to  pour  it  several  times  backward  and  forward 
upon  the  film,  and  finally  into  the  bottle.  This  operation  is 
performed  in  a  room  that  is  not  darkened  actinically ;  and, 
what  especially  is  an  essential  part  of  the  operation,  the 
film  so  prepared  is  exposed  for  a  few  minutes  at  least  to  dif- 
fused Hght..  The  intention  of  this  is  to  destroy  all  the-  germs 


TANNIN  AS  A  SENSITIZER. 


355 


of  stains  or  fogginess  which  would  be  manifested  afterward 
in  the  final  development. 

"  The  film  is  next  washed  in  several  waters,  in  order  to 
remove  as  much  as  possible  of  the  alkaline  iodide  which  has 
produced  its  effect ;  in  this  way  a  film  of  iodide  of  silver  is 
prepared,  which  is  altogether  insensitive  to  light,  and  in- 
capable of  instituting  the  reduction  of  the  developing  so- 
lutions. In  order  to  render  this  film  sensitive,  all  that  is 
required  is  to  pour  upon  its  surface,  in  the  dark-room  natu- 
rally, an  aqueous  solution  of  tannin,  containing  about  22 
grains  of  tannin  to  the  ounce  of  water.  This  being  done, 
the  plate  may  be  exposed  immediately ;  it  is  as  sensitive  as 
a  plate  sensitized  by  nitrate  of  silver. 

"  In  order  to  develop  the  latent  image,  the  plate  is  first 
washed  in  order  to  remove  all  excess  of  tannin ;  it  is  then 
submitted  to  the  action  of  a  solution  of  aceto-nitrate  of 
silver  containing  from  9  to  13  grains  to  the  ounce,  and 
afterward  to  that  of  sulphate  of  iron  or  pyrogallic  acid. 
In  other  respects  the  development  is  precisely  the  same  as 
in  the  usual  processes  ;  but,  what  is  remarkable  and  very 
advantageous,  is  the  fact  that  by  this  method  can  be  obtain- 
ed, certainly  and  without  great  precautions,  negatives  that 
are  very  neat,  very  vigorous,  and  without  stain. 

"  Instead  of  exposing  the  film  already  sensitized  by  tannin 
right  away,  it  may  be  put  away  to  dry,  in  order  to  be  used 
as  a  dry  plate  ;  it  will,  in  this  condition,  keep  much  longer 
than  if  nitrate  of  silver  were  present  on  its  surface.  Be- 
sides this,  plates  of  inert  iodide  of  silver  may  be  prepared 
beforehand,  dried  and  sensitized  by  the  aqueous  solution  of 
tannin,  or,  preferably  in  this  case,  by  an  alcoholic  solution. 
All  these  means,  I  repeat,  will  yield  excellent  results. 

"  I  give  here  only  one  method.  All  I  can  say  is,  that  this 
method,  which  may  be  applied  to  all  the  known  processes, 
requires  much  less  care,  and  especially  products  less  perfect 
as  to  their  special  and  chemical  condition,  than  is  the  case 
in  the  usual  processes  in  which  nitrate  of  silver  is  the 
sole  or  partial  sensitizer  of  the  iodide  of  silver." 

It  is  evident  from  the  preceding  course  of  experimentation 
of  Poitevin,  that  the  collodion  film  being  once  sensitive  to 
the  action  of  light  by  means  of  tannin,  the  alkaline  mode  of 
developing  can  be  properly  and  advantageously  applied. 
This  discovery  opens  a  wide  field  for  future  research  and 
beneficial  results  ;  as  regards  the  latter,  need  be  mentioned 
only  the  fact,  that  very  soon  we  shall  have  plates  of  glass 
already  prepared  with  the  inert  iodide  of  silver  in  the  raar- 
17 


356 


CHROMO-PHOTOGRAPHY. 


ket  for  the  use  of  the  practical  photographer  ;  the  only  task 
devolving  upon  him  being  simply  to  sensitize  the  plates  in 
the  dark-room  with  a  solution  of  tannin  previous  to  expo- 
sure. We  are  convinced  that  this  is  no  reverie.  It  remains 
for  the  manufacturer  to  devise  proper  means  for  effecting 
the  ends  in  view. 

Chromo-Photography  and  Positive  Printing  without 
the  Salts  of  Silver. 

This  process  has  made  decided  advances  since  the  publi- 
cation of  the  first  edition  of  the  Sunbeam.  Hitherto  it  has 
been  a  mere  chemical  recreation,  more  amusing  than  prac- 
tical. The  blue  prints,  first  produced  by  Dr.  Phipson,  in 
accordance  with  Herschel's  discovery  of  the  reduction  of 
the  persalt  of  iron  when  in  connection  with  the  organic 
matter  to  the  condition  of  protosalts  by  the  agency  of  light, 
were  always  defective.  For  the  prints,  whether  produced 
by  the  use  of  the  sesqui-chloride  of  iron,  the  oxalate  of  the 
sesqui-oxide,  or  the  double  oxalate  of  iron  and  ammoni° 
and  by  development  with  a  solution  of  ferrid-cyanide  of  po- 
tassium, Avere  scarcely  ever  free  from  a  blue  tinge  in  those 
parts  which  ought  to  be  white.  This  tinge  was  attributed 
to  the  undecomposed  peroxide,  whereby  Prussian  blue  re 
suited  on  immersion  in  the  ferrid-cyanide,  whereas  the 
picture  itself  was  formed  of  the  decomposed  protoxide  into 
Turnbull's  blue.  Knowing  that  the  former  pigment  is 
soluble  in  oxalic  acid,  whilst  the  latter  is  insoluble  in  this 
menstruum,  Carey  Lea,  Esq.,  has  succeeded  in  producing 
blue  pictures  in  which -the  whites  are  perfect.  His  method 
is  the  following : 

In  the  first  place,  a  solution  is  formed  of  the  double 
oxalate  of  the  peroxide  of  iron  and  ammonia.  Any  work 
on  chemistry  will  give  instruction  how  to  prepare  pure 
hydrated  peroxide  of  iron.  To  a  hot  solution  of  binoxalate 
of  ammonia  add  of  the  freshly-prepared  and  still  moist  per- 
oxide of  iron  as  long  as  it  is  dissolved ;  the  solution  is 
finally  evaporated,  and  allowed  to  crystallize.  The  crystals 
thus  obtained  is  the  double  salt  in  question,  which  must  be 
made  and  kept  in  the  dark-room. 

Sensitizing  the  Paper. 

Formula  for  Sensitizing  Solution. 

Rain-water,  5  ounces. 

Double  oxalate  of  iron  and  ammonia,    .    .      1  ounce. 

Prepare  and  filter  this  solution  in  the  dark-room.  Plain 


CHROMO-PHOTOGRAPHT. 


357 


or  unsalted  photographic  paper  is  floated  on  this  solution  for 
a  minute  or  more,  it  is  then  hung  up  to  dry.  So  prepared, 
the  paper  has  a  pale  yellow  color.  As  long  as  it  is  seclud- 
ed entirely  from  light  it  may  be  preserved  for  an  indefinite 
time. 

Exposing  the  Sensitized  Paper. 
This  operation  requires  but  very  little  instruction.  Fol- 
low the  ordinary  printing  process,  place  the  sensitized  sur- 
face upon  the  negative  in  the  printing  frame,  and  expose 
either  to  the  direct  rays  of  the  sun,  or  to  diffused  light.  In 
the  former  case  three  or  four  minutes  will  be  sufficient.  By 
this  means  a  faint  negative  is  produced  upon  the  paper  ;  for 
where  the  light  has  acted,  the  yellow  rust  has  become 
bleached  or  decolorized. 

Developing  the  Picture. 
The  prints  have  to  be  developed  immediately,  otherwise 
the  actinic  influence  becomes  annihilated. 

Formula  for  Developer. 

Ferrid-cyanide  of  potassium,  20  grains. 

Oxalic  acid,  .    .  20  " 

Water  from  12  to  15  ounces. 

The  prints  are  immersed  in  this  solution  for  two  or  three 
minutes.  The  image  starts  out  with  as  great  rapidity  as  in 
the  collodion  process  with  solution  of  protosulphate  of  iron  ; 
it  is  of  a  blue  color.  No  further  fixing  is  required  than  that 
of  washing  in  water  for  about  ten  minutes.  Too  much 
washing  is  injurious. 

Schwartz's  Simple  Process  for  Blue  Pictures. 
Float  the  papers  on  the  following  solution  in  the  dark- 
room.   The  solution  itself  must  be  prepared  in  the  dark- 
room ;  it  has  a  greenish  brown  color. 

Sensitizing  Solution. 
Sesqui-chloride  of  iron,  neutral  and  crystallized,     .    .  58  grains. 

Oxalate  of  ammonia,  crystallized,  53  " 

Ferrid-cyanide  of  potassium,  54  " 

Water,  1  pint. 

Dry  the  prints  partially,  and  expose  them  on  the  negative 
in  a  moist  condition.  By  this  exposure  the  image  is  brought 
out  of  a  deep  blue  color.  The  prints  are  afterward  fixed 
by  simple  washing. 

Marion  in  Paris  prepares  a  paper  for  sale,  at  the  sug- 
gestion of  Mr.  Motileff,  wThich,  when  exposed  for  twenty- 
five  to  thirty  minutes  under  a  negative,  exhibits,  when  wash- 


358 


CHROMOPHOTOGRAPHY. 


ed,  a  blue  print.  This  print  is  afterward  toned  to  an  inky 
black  by  immersion  first  in  an  alcoholic  solution  of  potassa, 
(four  grains  potassa  and  three  ounces  alcohol,)  which  turns 
the  image  yellow ;  it  is  next  washed  and  turned  black  by  a 
solution  of  gallic  acid  in  alcohol,  containing  thirty-five  grains 
of  the  acid  to  the  ounce  of  alcohol.  This  is  an  ink  picture, 
which  has  to  be  dried  without  washing. 

Prints  obtained  by  Schwartz's  process  will  undoubtedly 
turn  black  by  the  same  treatment,  so  that  there  will  be  no 
need  of  sending  to  Paris  for  MotilefFs  prepared  paper. 

Ink  pictures,  however,  are  any  thing  but  agreeable. 

Signor  Borlinettcfs  Process. 
In  the  first  place  make  the  two  following  solutions : 

(  Oxalic  acid,    ....    3  drachms.  J  Shake  the  mix- 
No.  1.        ■<  Distilled  water,  ...    18      "       >    ture  and  put 

(  Carbonate  of  iron,    .    .    6      "       )  aside  for  20  days. 

(  Citric  acid,  1  drachm.  )  Stir  the  mixture 

No.  2.        •<  Distilled  water,    ...     6     "       >•   and  put  aside 

(  Carbonate  of  iron,    .    .    3     "       )  also  for  20  days. 

After  this  time  decant  the  two  solutions,  and  measure  out 
as  follows : 

Of  No.  1,  1  drachm. 

Of  No!  2,   3  minims. 

Shake  the  mixture  and  apply  it  to  the  surface  of  paper  by 
a  tuft  of  cotton  wool  in  the  dark-room.  The  paper  soon 
dries,  and  is  ready  for  printing.  In  direct  sunlight  the  ex- 
posure is  shorter  than  that  required  for  a  silver  print ;  in 
diffused  light  it  is  longer. 

Developer. 

Alcohol,  15  drachms. 

Nitrate  of  silver,  30  grains. 

The  picture  brought  out  by  this  developer  is  of  a  splendid 
black,  which  is  well  washed  and  dried.  It  is  then  placed  in 
a  ten  per  cent  solution  of  citric  acid,  and  kept  in  continual 
motion,  in  order  to  preserve  an  equality  of  tone.  The  print 
is  afterward  washed  in  several  changes  of  water,  and  then 
immersed  for  two  minutes  in  a  weak  solution  of  ammonia. 
Finally  the  pictures  are  again  carefully  washed  and  dried. 

Process  without  the  Salts  of  Silver. 
By  this  process  prints  can  be  obtained  of  a  variety  of  tones, 
some  of  which  resemble  those  produced  by  the  salts  of  silver 
on  albumen  paper.  It  has  been  elaborated  by  an  indefat- 
igable German,  Mr.  Obernetter,  engaged  in  one  of  the  most 
reliable  laboratories  in  Munich. 


PROCESS  WITHOUT  THE  SALTS  OF  SILVER. 


359 


Take  common  unsalted  photographic  paper  and  float  it  in 
the  following  solution  : 


Sensitizing  Solution. 

Water,  12|  ounces. 

Solution  of  sesqui-chloride  of  iron,  sp.  gr.  1.53  to  1.6,  .  78  grains. 
Chloride  of  copper,  crystallized,   600  grains. 


Hydro-chloric  acid,  pure  and  concentrated,  .    .    .    .    72  grains. 

The  paper  is  allowed  to  remain  in  this  solution  for  about 
two  minutes.  It  is  then  removed  and  hung  up  to  dry.  It 
is  not  absolutely  necessary  to  perform  the  operation  in  the 
dark-room,  but  is  probably  to  be  recommended.  Paper 
thus  prepared  is  endowed  with  remarkable  properties.  Age 
does  not  seem  to  make  any  change  in  its  sensitiveness, 
which  is  about  one  third  greater  than  with  albumen  paper. 

Exposure. 

The  paper  is  placed  upon  the  negative  as  in  the  common 
printing  process,  and  exposed  to  the  direct  rays  of  the  sun, 
or  to  diffused  light.  The  length  of  time  has  to  be  learned 
by  experience.  After  exposure  the  picture  is  either  latent, 
or  at  the  most,  of  a  faint  yellow  color.  It  has  to  be  devel- 
oped immediately,  as  the  image  impairs  gradually,  until 
finally  no  vestige  is  left,  and  the  paper  may  be  exposed  a 
second  time  without  any  further  preparation. 

Fixing  Solution. 


Water,  12£  ounces. 

Sulpho-cyanide  of  potassium,     .    .     48  to  72  grains. 

Concentrated  sulphuric  acid,  6  grains. 

Sensitizing  solution,  60  to  120  grains. 


As  soon  as  the  paper  is  removed  from  the  printing  frame, 
it  is  floated  on  the  fixing  solution,  picture  side  downward, 
for  three  or  four  minutes,  taking  care  to  agitate  the  fluid  as 
little  as  possible ;  it  is  then  immersed,  and  another  print  is 
floated  in  the  same  manner,  and  thus  you  proceed  until  all 
the  prints  are  fixed,  or  the  vessel  is  full.  Fresh  solution  is 
gradually  added  in  order  to  keep  up  its  strength.  The  bath 
improves  by  age. 

By  this  process  cyanide  of  copper  is  precipitated  upon  all 
those  parts  upon  which  light  has  acted.  The  time  of  im- 
mersion in  the  fixing  solution  depends  upon  the  method  to 
be  afterward  adopted ;  it  ranges  from  five  minutes  to  half 
an  hour. 

If  the  print  be  allowed  to  remain  for  twenty-four  hours, 
the  deposition  is  so  great  as  to  exhibit  the  picture  in  relief. 
On  removal  from  this  solution,  the  prints  are  placed  in 


360 


CELESTIAL  PHOTOGRAPHY. 


water  for  about  an  hour,  during  which  time  the  water  is 
changed  several  times.  They  are  then  taken  out  and  dried. 
In  this  condition  they  may  be  stored  away,  or  toned  imme- 
diately. 

Toning  of  the  Prints. 

It  happens  frequently  that  the  image  disappears  in  the 
washing ;  this  need  not  excite  any  alarm,  for  the  nucleus  is 
still  in  the  paper,  and  the  image  appears  with  great  vigor 
and  beauty  when  toned.  In  the  first  place  immerse  the 
prints  in  the  following  solution  : 

Water,  6  ounces. 

Ferrid-cyanide  of  potassium,   .  from  180  to  300  grains. 

In  this  solution  the  pictures  become  red,  which  gradually 
increases  in  intensity,  until  they  finally  assume  a  splendid 
velvety  deep  red.  In  order  to  obtain  the  requisite  tone, 
which  in  the  final  operation  resembles  that  obtained  by  the 
silver  printing  process,  an  hour's  immersion  will  be  quite 
sufficient.  The  prints  are  then  removed  and  washed  in  sev- 
eral changes  of  water  until  the  latter  ceases  to  be  tinged 
yellow.  A  quarter  of  an  hour  is  sufficient  for  this  opera- 
tion. The  next  step  consists  in  immersing  the  prints  in  the 
following  solution : 

Water,  20  to  30  drachms. 

Proto-sulphate  of  iron,  10  " 

Sesqui-chloride  of  iron,  ....  4  " 
Hydrochloric  acid,  8  " 

In  this  solution  they  undergo  the  following  gradation  of 
color:  First  red,  then  reddish  violet,  blue-violet,  black,  and 
greenish  black.  The  most  beautiful  purple-violet  tones  are 
obtained  by  leaving  them  in  the  iron  solution  until  they  be- 
come green-black.  They  are  then  gently  washed  and  flow- 
ed for  a  moment  with  a  dilute  solution  of  sub-acetate  of 
lead. 

After  drying,  the  prints  are  floated  on  albumen,  and  then 
hung  up  to  dry.  In  this  state  they  resemble  albumen 
pictures. 

Celestial  Photography. 

In  this  department  of  Natural  Science,  it  gives  us  infinite 
pleasure  to  record  the  progress  made  by  one  of  our  own 
countrymen.  The  advance  alluded  to  is  the  photographic 
delineation  of  the  Moon  by  means  of  a  Reflecting  Telescope, 
constructed  by  Dr.  Henry  Draper,  Professor  in  the  Univer- 
sity of  New-York. 


CELESTIAL  PHOTOGRAPHY. 


361 


Since  the  invention  of  the  Telescope  in  the  seventeenth 
century,  an  ardent  desire  arose  among  astronomers  to  tran- 
scribe to  paper  an  accurate  representation  of  this  our  near- 
est companion  among  the  stellar  host.  Even  to  the  naked 
eye  the  concave  part  of  the  moon  in  crescentic  form  exhib- 
ited an  irregular  curve,  which,  by  the  telescope,  became  con- 
verted into  illuminated  protuberances  and  dark  indentations, 
which  were  soon  recognized  as  the  pinnacles  of  vast  moun- 
tains, and  the  declivities  between  mountain  ranges. 

Several  selenographical  observers  have  furnished  the  sci- 
entific inquirer  with  very  accurate  charts  both  of  the  moon 
when  full  and  when  crescentic,  of  which  perhaps  those  of 
Baer  and  Maedler  are  the  most  to  be  relied  upon.  Their 
map  of  the  full  moon  is  thirty-seven  inches  in  diameter,  and 
is  a  masterpiece  of  patient  and  faithful  delineation. 

But  as  soon  as  Photography  took  its  position  as  a  branch 
of  Natural  Science,  it  became  recognized  at  an  early  period 
as  one  of  the  most  unerring  helpmates  to  astronomical  in- 
vestigations. In  fact,  it  is  now  known  that  the  prepared 
aim  of  collodion  is  sensitive  to  impressions  from  objects 
whose  light  had  given  no  intelligence  of  their  presence  when 
viewed  by  the  telescope  ;  in  short,  that  certain  protuber- 
ances or  mountains  on  the  sun's  disk  were  made  visible  by 
actinism  on  iodized  collodion,  which  were  invisible  in  the 
telescope.  It  is  no  wonder,  then,  that  to  photograph  the 
moon's  disk  has  always  been  a  favorite  branch  of  the  Heli- 
graphic  art  with  the  student  in  science.  As  early  as  1840, 
Professor  J.  W.  Draper  produced  pictures  of  our  satellite, 
of  one  inch  in  diameter,  which  were  presented  to  the  New- 
York  Lyceum  of  Natural  History.  Since  then  his  son 
has  constructed  a  very  superior  reflecting  instrument,  the 
largest  in  America,  by  which  he  has  succeeded  in  obtain- 
ing very  large  photographs  of  the  moon.  The  instrument 
is  located  at  Hastings,  near  New- York.  The  Observatory 
is  twenty  feet  square  and  twenty-two  feet  high,  and  is  fur- 
nished besides  with  other  appropriate  buildings  for  photo- 
graphic manipulations. 

All  the  arrangements  are  very  ingeniously  made.  The 
silvered  mirror,  by  which  the  image  of  the  moon  is  obtain- 
ed, is  the  work  of  the  Professor  himself. 

A  full  description  of  the  Observatory,  the  telescope,  and 
the  purposes  for  which  they  are  designed,  is  being  publish- 
ed at  Washington  by  the  Smithsonian  Institute. 


362 


swan's  carbon  process. 


New  Carbon  Process,  by  Mr.  Swan.  * 
This  process  is  pronounced  by  reliable  judges  to  be 
superior  to  its  predecessors.  Prints  obtained  by  it  are 
endowed  with  all  the  complete  detail  of  the  best  silver  pic- 
tures, and,  in  many  instances,  surpass  them.  It  is  immaterial, 
in  a  great  measure,  what  coloring  matter  is  employed,  as  long 
as  it  is  in  the  form  of  the  most  impalpable  powder. 

The  process  is  patented ;  but  the  details  of  the  conditions 
which  will  permit  photographers  to  practise  it  have  not  yet 
been  published.  It  is  to  be  hoped,  and  we  believe  it  is 
Mr.  Swan's  liberal  intention,  that  amateurs  be  allowed  to 
use  the  process  and  prosecute  further  researches,  as  long  as 
no  pecuniary  advantage  is  derived  from  such  a  favor.  If 
the  carbon  prints  by  this  process  shall  represent  nature, 
the  first  step  consists  in  obtaining  an  inverted  negative.  Any 
experienced  photographer  is  acquainted  with  the  method 
pursued  in  the  preparation  of  such  a  negative.  This, 
however,  is  not  absolutely  necessary,  because  Mr.  Swan 
has  devised  an  expedient  by  which  the  same  end  can  be 
attained. 

The  next  step  is  then  to  prepare  the  flexible  film  for  the 
reception  of  the  image.  A  plate  of  smooth  glass  is  coated 
with  plain  or  uniodized  collodion  of  good  body,  and  put 
aside  to  dry.  In  this  way  several  plates  are  coated  and 
preserved  for  use. 

Sensitizing  Solution. 

Gelatine,  4  ounces. 

Water,  16  * 

Soak  the  gelatine  for  half  an  hour  in  cold  water,  and  then 
apply  a  gentle  heat,  which  will  soon  dissolve  it.  When 
nearly  cool,  add  the  white  of  one  egg  already  well  beaten, 
and  stir  up  the  mixture  intimately.  The  more  intimate  the 
mixture,  the  more  effectually  will  the  impurities  be  removed 
when  it  is  heated  to  a  boiling  temperature  ;  for  the  albumen 
coagulating  carries  them  down,  and  leaves  the  solution  quite 
clear,  which  is  separated  whilst  warm  by  filtration  through 
a  moist  filter. 

Next,  dissolve  two  ounces  of  loaf  sugar  in  a  sufficient 
quantity  of  water  so  as  to  make  up  the  loss  by  coagulation 
and  filtration,  and  add  the  mixture  to  the  gelatine. 

This  solution  is  now  colored  with  any  desired  pigment. 
Take,  for  instance,  Chinese  ink,  and  rub  it  down  on  a  pallet 

*  For  full  details  of  Swan's  Carbon  Process,  as  published  by  him  in  1868,  see  page 
337. 


SWAN'S  CAKBON  PROCESS. 


363 


until  the  proper  quantity  has  been  obtained.    Mix  it  with  a 
little  water  and  filter  ;  then  add  this  to  the  gelatine. 
Now  prepare  the  following  solution  : 

Bichromate  of  ammonia,  1  ounce. 

Water,  3  ounces. 

Take  the  gelatine  solution  already  colored  and  the  bi- 
chromate solution,  at  this  stage,  into  the  dark-room  for  the 
subsequent  manipulations,  and  prepare  the  following  mix- 
ture : 

Gelatine  solution,  from  8  to  10  ounces. 

Bichromate  solution,  1  ounce. 

This  mixture  is  now  sensitive  and  is  ready  for  use.  It  is 
best  to  apply  it  always  recently  made. 

Take  one  of  the  collodion-coated  plates,  warm  it  gently, 
as  also  the  sensitive  mixture,  and  pour  the  latter  in  a  uniform 
film  upon  the  collodion,  and  put  the  plate  on  a  levelling 
stand  in  a  warm  corner  of  the  dark-room  to  dry.  In  a  few 
hours  the  film  will  be  thoroughly  desiccated,  and,  by  cutting 
along  the  edges  with  a  sharp  knife,  it  may  be  stripped  off 
from  the  glass  as  a  translucent  pellicle. 

Printing  Operation. 
Place  the  negative  in  the  common  printing  frame  and  the 
translucent  pellicle  upon  it  with  the  collodion  films  in  con- 
tact. Lay  upon  the  gelatine  film  a  piece  of  soft  cloth,  and 
apply  the  pressure  board  as  usual.  Expose  for  about  five 
minutes. 

Development  of  the  Picture, 

Returning  to  the  dark-room,  the  film  is  now  pasted  upon 
a  piece  of  paper  by  means  of  starch  or  india-rubber  cement, 
the  collodion  side  being  next  to  the  paper.  When  dry,  the 
latter  is  placed  in  warm  water  at  a  temperature  of  about 
100°.  By  this  operation  the  parts  that  have  not  been  im- 
pressed by  light  are  dissolved,  whilst  the  remaining  parts 
which  form  the  picture,  having  become  insoluble  in  water, 
adhere  to  the  paper. 

The  reader  will  observe  here  that  Swan  has  availed  him- 
self of  the  expedient  made  use  of  by  Fargier,  (vide  page 
281,)  and  first  discovered  by  Mr.  Burnett.  Several  changes 
of  water  are  required  before  the  picture  is  quite  clear.  It  is 
better  to  let  the  prints  soak  for  an  hour  or  two,  after  which 
they  are  dried  and  thus  completed. 

If  the  prints  are  obtained  from  an  inverted  negative, 
they  will  be  true  representations  of  the  objects  depicted ;  if 


364 


swan's  carbon  process. 


otherwise,  they  will  be  laterally  inverted.  In  such  cases,  the 
author  of  the  process  uses  india-rubber  cement  in  the  first 
place,  and  now  covers  the  surface  of  the  print  with  starch- 
paste  and  applies  a  fresh  piece  of  paper.  When  dry,  the  first 
paper  is  easily  detached  by  lifting  it  from  the  film. 

Since  the  preceding  remarks  on  the  Carbon  Process  were 
written,  Mr.  Swan  has  brought  his  Process  to  a  great  de- 
gree of  perfection,  and  we  publish,  commencing  at  Chapter 
XL V.,  page  337,  a  full  account  of  all  the  manipulations  in 
Swan's  Perfected  Carbon  Process,  as  published  by  him  in 
1868.  This  Chapter  XLV.  was,  in  our  previous  editions, 
devoted  to  the  subject  of  Weights  and  Measures,  which  we 
have  now  placed  at  the  end  of  the  book. 


CHAPTER  XLVII. 


THE  WOTHLYTYPE — SUTTON'S    DRY    PROCESS — THE  RAISES" 

PROCESS  THE     PORCELAIN    PICTURE — ANILINE  PRINTING 

PROCESS — COLLODIO-CHLORIDE  PROCESS — EBURNEUM  PRO- 
CESS— GLAZED  PHOTOGRAPHS — MAGNESIUM  DUPLEX  TYPE 

 REDUCTION  OP  WASTES  THE  IVORYTYPE  PHOTO-RELIEF 

printing — the  foxtype,  etc. 

The  Wothlytype; 

A  PROCESS  FOR  PRINTING  ON  PAPER  WITHOUT  EMPLOYING  EITHER  THE  CHLO- 
RIDE, IODIDE,  OR  BROMIDE  OP  SILYER,  AND  WITHOUT  DEYELOPMENT. 

Prints  can  be  obtained  by  this  process,  which,  for  soft- 
ness, tone,  and  brilliancy,  can  scarcely  be  surpassed  by  silver 
prints  ;  the  tone  is  quite  characteristic  and  charming. 

Paper  is  coated  with  a  sensitive  collodion,  and  when  dry 
is  submitted  beneath  a  negative  to  the  influence  of  light  in 
the  usual  manner.  When  the  intensity  of  the  shades  is  suf- 
ficiently deep,  the  print  is  fixed  in  an  acid-bath,  and  after- 
ward washed  and  toned.  No  development,  it  will  be  per- 
ceived, is  required.  The  details  of  the  process  are  not  yet 
sufficiently  succinct ;  but,  as  far  as  we  have  been  enabled 
to  ascertain  them  from  the  French  specification,  they  stand 
as  follows  : 

Preparation  of  the  Sensitive  Salts. 

The  author  recommends  the  operator  to  treat  the  nitrate 
of  uranium  of  commerce  by  the  following  process  : 

Dissolve  a  given  quantity  of  nitrate  of  uranium  in  water ; 
to  this  solution  add  ammonia  as  long  as  a  precipitate  is 
thereby  produced.  This  precipitate,  after  subsidence,  is 
separated  from  the  supernatant  liquid,  and  carefully  washed 
in  several  changes  of  water.  It  is  finally  dissolved  in  pure 
nitric  acid,  by  the  aid  of  heat,  taking  care  to  have  an  ex- 
cess of  the  precipitate  in  the  acid,  in  order  that  all  the  acid 
may  be  completely  neutralized.  The  author  supposes  that 
thus  he  has  obtained  a  double  salt  of  uranium  and  ammo- 
nia. This  is  an  error ;  he  has  simply  produced  nitrate  of 
uranium,  sometimes,  probably,  in  a  purer  condition  than  it 
was  at  the  commencement  of  the  operation.    With  this 


366 


THE  WOTHLYTYPE. 


prepared  specimen  of  nitrate  of  uranium  proceed  to  the  fol- 
lowing formulas  : 

Formula  No.  1. 

No  A  I  Nitrate  of  cranium,    .    .    6  drachms.  )  Disgolve 
\  Distilled  water,    .    .    .    .  3  drachms,  f JJlssolve- 

No  B  -S  Nitrate  of  silver  .  .  .  15  grains.  [  Dissolve 
JN0*-b-  I  Distilled  water,    .    .    .    .  30  minims.  )  ^lssolve- 

Mix  the  two  solutions  together  and  put  the  mixture  in  a 
warm  place  to  crystallize.  This  is  a  double  salt  —  the  ni- 
trate of  silver  and  uranium. 

Formula  No.  2. 

Nitrate  of  silver  and  uranium,   3  drachms 

Alcohol,  8  drachms. 

Distilled  water,  15  minims. 

Nitric  acid,  1  minim. 

With  this  solution  the  collodion  is  to  be  sensitized. 

Preparation  of  the  Resinized  Collodion. 

Formula  No.  3. 

(  Alcohol,  10  ounces. 

No.  A.  <  Ether,  30  ounces. 

(  Pyroxyline,   220  grains. 

{Canada  balsam,  1  drachm. 
Castor  oil,   1  drachm. 
Ether  sufficient  to  cause  the  solution  to 
press  through  the  filter. 

The  solution  B  is  now  to  be  evaporated  on  a  water-bath 
until  it  has  the  consistence  of  oil. 

Formula  No.  4. 

Resinized  Collodion. 

Take  of  plain  collodion,  No.  A,  20  ounces. 

Take  of  Canada  balsam,  etc.,  No.  B,    .    .    .    .10  minims. 

Preparation  of  the  Sensitive  Collodion. 
Formula  No.  5. 
Sensitive  Collodion. 

Take  of  the  solution  for  sensitizing  collodion, 

Formula  No.  2,  '   .    6  drachms. 

Take  of  resinized  collodion,  .       ...    12  drachms. 
Take  of  nitric  acid,  2  drops  or  more. 


THE  WOTHLYTYPE. 


367 


This  collodion  must  be  prepared  in  the  dark-room,  and 
preserved  in  a  bottle  well  protected  from  actinic  rays  by 
means  of  several  folds  of  orange-colored  paper  or  cloth.  A 
tin  case  surrounding  the  bottle  is  about  the  best  pro- 
tection. 

Preparation  of  the  Paper  for  receiving  the  Sensitive  Collo- 
dion. 

Formula  No.  6. 

Arrowroot  starch,  1  ounce. 

Water,  34  ounces. 

Acetate  of  lead,  10  drops. 

To  this  mixture,  heated  to  a  temperature  of  100°  Fahr., 
add  four  ounces  of  albumen.  Stir  the  ingredients  intimate- 
ly together.  It  is  then  ready  for  use.  The  sheets  of  paper 
may  be  either  floated  on  this  sizing  for  about  five  minutes, 
or  may  receive  the  proper  amount  of  sizing  by  means  of  a 
soft,  clean  sponge.  If  the  latter  plan  be  adopted,  the  paper 
is  placed  upon  a  flat  board  or  a  plate  of  glass.  Apply  the 
sponge  upon  the  middle,  and  then  work  to  the  right  and  to 
the  left  from  the  middle  until  the  whole  surface  is  covered ; 
now  equalize  the  longitudinal  streaks  by  operating  with  the 
sponge  in  the  same  manner  from  the  middle,  but  trans- 
versely to  the  preceding  direction,  until  the  surface  of  the 
paper  is  evenly  covered  with  the  size. 

The  sheets  so  covered  are  finally  hung  up  and  dried. 

Coating  the  Paper  with  Collodion. 

Take  a  smooth  board,  somewhat  larger  than  the  sheet 
of  paper  to  be  coated,  and  pin  three  corners  of  the  sheet  to 
the  board.  The  collodion  is  then  poured  upon  the  paper, 
as  if  it  were  a  plate  of  glass ;  the  excess  of  collodion  is  al- 
lowed to  flow  off  into  the  vial  by  the  corner  which  is  not 
pinned  to  the  board.  With  a  little  practice,  paper  can 
thus  be  coated  with  collodion  as  easily  and  dexterously  as  a 
negative  plate. 

Of  course  the  paper  which  is  thus  coated  is  the  arrow- 
root paper,  as  prepared  by  the  preceding  formula. 

Hang  up  the  collodionized  sheet  in  the  dark-room  to  dry. 

Printing. 

This  operation  is  in  no  respect  different  from  that  of 
printing  on  sensitized  albumen.  Place  the  paper  beneath 
the  negative,  and  expose  to  the  direct  rays  of  the  sun  or  to 
diffused  light.    The  paper  will  bear  slightly  over-printing 


368 


sutton's  dry  process. 


Fixing  Solution. 
Formula  No.  7. 

Distilled  water,   40  ounces. 

Acetic  acid,   1  ounce. 

Hydrochloric  acid,  1  ounce. 

The  prints  are  placed  in  this  solution  for  ten  or  fifteen 
minutes  and  then  washed  in  two  or  three  changes  of  water. 

Toning. 

It  is  not  absolutely  necessary  to  tone  the  prints,  but  they 
are  improved  by  this  operation.  Any  of  the  ordinary  gold 
toning  solutions  may  be  used  in  this  process.  Finally, 
wash  the  prints  thoroughly  and  hang  them  up  to  dry. 

To  secure  permanency  in  the  prints,  it  is  an  advantage  to 
fix  them  after  toning  in  a  solution  of  hyposulphite  of  soda, 
and  then  to  wash  them  as  usual  and  dry  them. 

Sutton's  Rapid  Dry  Tannin  Process. 
Preparation  of  the  Plates. 

Plate  glass  is  recommended  in  this  process,  because  it  is 
less  liable  to  break  by  pressure  in  the  printing-frame,  and 
because  it  can  be  more  easily  brought  into  contact  with  the 
paper  than  ordinary  glass. 

The  edges  are  first  of  all  abraded  by  means  of  a  file  or  a 
sand-stone. 

Fresh  plates  of  glass,  that  is,  such  as  have  not  been  used 
before,  are  rubbed  with  a  piece  of  flannel  dipped  in  a  thick 
mixture  of  chalk  and  water,  which  is  afterward  removed 
beneath  the  tap  with  a  sponge ;  they  are  next  immersed 
in  a  bath  of  dilute  acetic  acid,  in  order  to  neutralize  the 
alkaline  earth,  and  again  well  rinsed,  and  finally  dried  with 
a  clean  old  linen  cloth,  which  is  used  for  this  purpose  alone. 
This  cloth,  naturally,  must  be  quite  free  from  any  trace  of 
alkali,  as  of  soap,  etc. 

Plates  that  have  been  used  before  may  be  immersed  in  a 
bath  of  dilute  nitric  or  chromic  acid,  and  then  washed,  etc., 
as  just  indicated. 

It  is  well  to  have  two  cloths — one  for  each  hand — when 
wiping  the  plates,  for  then  the  plates  do  not  come  in  con- 
tact with  the  hands.  Rub  off  all  chalk-powder  from  the 
edges,  and  dry  the  plates  by  artificial  heat ;  finally,  place 
them  in  a  clean  plate-box  until  required  for  use. 

Immediately  before  use  each  plate  is  thoroughly  dried 


sutton's  dry  process. 


369 


and  polished  by  a  piece  of  clean  buckskin,  the  plate  being 
held  between  the  folds  of  a  silk  handkerchief  in  the  left 
hand  during  the  operation.  It  is  then  ready  for  the  next 
operation. 

Substratum  for  preventing  the  Collodion  Film  from  slid 

ing  off. 

Dissolve  one  grain  of  India-rubber  or  gutta-percha  in  an 
ounce  of  benzole  or  of  chloroform.  Each  plate  when  pol- 
ished and  dry  is  coated  with  this  solution,  which  is  poured 
upon  the  surface  in  the  same  manner  as  collodion.  The 
film  is  then  dried  by  artificial  heat.  When  this  operation 
is  properly  performed,  the  surface  which  has  received  the 
film  is  undistinguishable  from  the  one  which  has  received 
no  coating ;  in  consequence  of  this,  it  is  requisite  to  indicate 
the  coated  surface  by  means  of  a  diamond  scratch  or  by  some 
other  expedient. 

Sometimes  the  plates  are  simply  varnished  round  the 
edges  to  the  depth  of  one  eighth  of  an  inch  with  the  same 
varnish.  The  author  does  not  recommend  the  use  of  either 
gelatine  or  albumen  in  solution  for  the  purpose  just  men 
tioned. 

Coating  the  Plates  with  Collodion. 

Formula  for  Plain  Collodion. 

Pyroxyline,  3  drachms. 

Ether,  concentrated,  150  drachms. 

Alcohol,  90  drachms. 

Iodizing  Solution. 

Iodide  of  cadmium,   8  drachms. 

Bromide  of  cadmium,  3  drachms. 

Alcohol,  sp.  gr.  .810,   240  drachms. 

Bromo-iodized  Collodion. 

Plain  collodion,  3  fluid  ounces. 

Iodizing  solution,  1  fluid  ounce. 

After  the  mixture  has  been  well  shaken,  it  is  put  aside  for 
a  few  hours  to  ripen  and  settle.  Decant  the  clear  superna- 
tant part  by  means  of  a  siphon  or  filter.  This  collodion  is 
quite  colorless,  and  can  be  kept  a  long  time  in  a  cool  place 
without  undergoing  decomposition. 

The  pyroxyline  recommended  by  the  author  must  be  of 
such  a  nature  as  to  form  a  clear  solution  and  free  from  any 
acid  reaction,  and  the  ether  and  alcohol  must  be  neutral  and 
devoid  of  impurities. 

Coat  the  plates  with  this  collodion  in  the  usual  manner. 


370 


button's  dry  process. 


Sensitizing  the  Film. 
The  nitrate  of  silver  bath  is  composed  as  follows  : 

Nitrate  of  silver,  4  ounces. 

Distilled  water,   64  ounces. 

Nitric  or  acetic  acid,   20  minims. 

Immerse  a  collodionized  plate  in  this  bath  for  a  number 
of  hours,  the  solution  is  then  ready  for  use.  The  bath  works 
best  when  freshly  prepared. 

Use  glass  vessels  for  the  subsequent  operations  in  prefer- 
ence to  any  other. 

The  collodionized  plate  is  retained  in  the  bath  until  the 
film  has  assumed  a  greenish-yellow,  cream-like  color.  This 
will  be  effected  by  an  immersion  of  three  minutes  in  summer 
and  of  six  in  winter.  The  plate  is  then  taken  out  and  rinsed 
until  the  oily  appearance  has  been  removed ;  it  is  then  al- 
lowed to  drain,  after  which  it  is  immersed  in  another  bath, 
containing  distilled  or  rain-water,  where  it  remains  until 
another  plate  has  been  coated  with  collodion  and  sensitized. 
The  plate  is  moved  about  in  the  water  several  times.  As 
soon  as  another  plate  is  ready  to  take  its  place,  the  first 
plate  is  taken  out  and  washed  in  rain-water,  by  allowing  it 
to  fall  upon  every  part  of  the  film  from  a  height  of  two  or 
three  inches. 

Tannin  Solution. 

Tannin,        .   2  drachms.. 

Distilled  water,  8  ounces. 

Dissolve  and  filter  the  solution. 

A  small  portion  of  the  filtered  tannin  solution  is  poured 
upon  the  washed  collodion  film  and  kept  in  motion  a  short 
time;  it  is  then  poured  away  and  a  fresh  solution  takes  its 
place.  This  being  done,  the  excess  of  tannin  is  poured  off, 
and  the  plate  is  reared  on  one  corner  on  a  piece  of  clean  blot- 
ting-paper, or  placed  in  the  drying-box  to  dry  spontaneously. 
Artificial  heat  is  applied  only  in  order  to  remove  the  last 
traces  of  moisture,  when  the  plates  have  to  be  kept  for 
some  time. 

If  the  plates  are  to  be  kept  a  long  time,  they  are  tied  to- 
gether in  pairs,  the  collodion  films  facing  each  other,  and 
prevented  from  coming  in  contact  by  means  of  a  strip  of 
card-board  all  round  the  edges.  Each  pair  is  then  folded 
up  in  three  folds  of  yellow  paper  or  cloth  to  prevent  all  in- 
gress of  white  light.  Previous  to  thus  packing  them  up  in 
pairs,  each  plate  is  well  dried  over  a  hot  plate  of  iron,  or  a 
copper  vessel  filled  with  hot  water. 


sutton's  dry  process. 


371 


Exposure  of  the  Plate, 


There  is  a  wide  scope  for  the  length  of  the  exposure  of  a 
tannin  plate,  but  the  safest  plan  is  to  expose  longer  than 
would  be  required  for  a  wet  plate.  The  longer  the  expos- 
ure, the  greater  the  harmony  of  the  negative. 

Considerable  over-exposure  gives  rise  to  a  defect  called 
blurring,  which  is  manifested  when  the  lights  and  shades  of 
the  negative  encroach  upon  one  another.  This  is  an  optical 
defect,  and  is  caused  by  the  reflection  of  the  rays  of  light 
from  the  posterior  surface  of  the  glass  plate,  being  always 
most  visible  where  the  rays  are  most  oblique. 

In  landscape  photography  it  is  recommended  to  give  the 
sky  less  exposure  than  the  foreground. 

Before  the  plate  is  placed  in  the  holder,  or  at  least  before 
it  is  developed,  in  case  no  previous  substratum  of  India- 
rubber,  gelatine,  etc.,  has  been  used,  it  is  necessary  to  var- 
nish the  edges  of  the  film  with  the  India-rubber,  etc.,  so- 
lution. 


The  development  of  a  tannin  plate  is  the  most  critical 
part  of  the  whole  manipulation  of  the  tannin  process,  and 
requires  most  judgment  and  experience,  the  appearance  of 
the  negative  with  the  alkaline  developer  being  so  very  dif- 
ferent from  that  with  the  common  wet  process.  By  reflect- 
ed light,  negatives  developed  by  the  alkaline  process  appear 
quite  fogged ;  it  is  only  by  transmitted  light  they  exhibit 
their  beautiful  properties.  Other  negatives  may  be  more 
beautiful  to  look  at,  but  these  produce  the  best  prints. 

If  it  is  known  beforehand  that  the  plate  has  been  over- 
exposed, it  is  better  to  make  use  of  the  acid  developer  con- 
taining nitrate  of  silver. 

The  development  of  a  negative  by  the  alkaline  develop- 
ment is  divided  into  two  distinct  operations  :  in  the  first 
place,  the  development  proper,  by  which  the  picture  is  made 
visible  ;  and  secondly,  the  intensifying  of  the  image,  by 
means  of  which  the  feeble  details  of  the  picture  are  made 
sufficiently  dense. 

To  bring  out  the  latent  image  with  the  alkaline  developer 
the  two  following  solutions  are  required  : 


XT    ,  (  Bicarbonate  of  soda,    .  10  grains.  )  m  u  j  u  /• 

No'     j  Water,    .....      1  ounce.  \  To  be  filtered  before  use' 


Development  of  the  Image. 


No.  2. 


\  Pyrogallic  acid, 
\  Absolute  alcohol, 


10  grains. 
1  ounce. 


372 


sutton's  dry  peocess. 


To  develop  the  picture,  measure  out  one  ounce  of  water, 
to  which  add  one  drachm  of  the  soda  solution,  and  fifteen 
minims  of  the  pyrogallic  acid  solution.  In  the  mean  while 
the  exposed  negative  film  has  been  uniformly  covered  with 
water  so  as  to  moisten  it ;  the  pyrogallic  acid  mixture  is 
well  shaken,  and  then  poured  upon  the  moistened  film  and 
moved  about  so  as  to  cover  every  part.  In  a  few  seconds 
the  sky  appears  and  the  high  lights  ;  in  two  or  three  min- 
utes the  darker  details  of  the  shadows  present  themselves  ; 
but  the  negative  is  quite  thin  and  can  not  be  made  more 
dense  by  this  developer.  If  a  picture  is  required  to  be  en- 
dowed with  much  contrast,  the  developing  process  is  soon 
brought  to  a  close ;  if,  on  the  contrary,  the  negative  is  re- 
quired to  be  very  soft  and  harmonious,  and  more  replete 
with  detail,  the  development  is  continued  much  longer. 
The  rule  is,  to  give  a  long  development  to  a  short  exposure, 
and  a  short  development  to  a  long  exposure.  » 

The  negative,  at  this  stage,  is  thoroughly  washed,  in  order 
to  remove  every  trace  of  the  alkaline  developer,  which,  if 
any  remained,  would  be  apt  to  fog  the  plate  in  the  subse- 
quent treatment. 

The  negative  is  now  of  a  light  brown  color  by  reflected 
light,  and  of  a  reddish-brown  color  by  transmitted  light ;  it 
is  easily  intensified. 

If  the  exposure  has  been  long,  it  may  happen  that  the 
picture  may  appear  before  development,  because  both  the 
bromide  and  iodide  of  silver  in  combination  with  tannin  are 
blackened  by  light. 

The  alkaline  developer  must  be  used  immediately  after 
its  preparation,  as  it  will  not  keep. 

Intensifying  the  Negative. 
In  the  first  place,  prepare  the  following  solutions  : 


(  Pyrogallic  acid,  2  grains. 

No.  1.  ■<  Glacial  acetic  acid,   .  20  minims. 

(  Distilled  water,  1  ounce. 

(  Nitrate  of  silver,   20  grains. 

No.  2.  •<  Glacial  acetic  acid,  .   20  minims. 

(  Distilled  water,  1  ounce. 


The  alkaline  developer  having  been  carefully  removed  by 
washing  from  the  developed  picture,  a  sufiicient  quantity 
of  the  acid  pyrogallic  acid  solution  No.  1,  in  a  vial  for  this 
purpose,  is  poured  upon  the  film,  in  order  to  neutralize  any 
remaining  trace  of  the  carbonated  alkali,  and  returned  to 


button's  dry  process. 


the  vial.  Five  drops  of  the  acid  silver  solution  -(supposing 
the  plate  is  of  the  stereoscopic  size)  are  now  added  to  the 
mixture  in  the  vial ;  the  mixture  is  well  shaken  and  then 
applied  to  the  plate  in  the  usual  manner  of  intensifying. 
Gradually  the  whole  film  becomes  slightly  fogged ;  but  this 
is  of  no  consequence,  for  the  shades  remain  quite  transparent 
by  transmitted  light.  As  soon  as  the  dense  parts  of  the 
negative  have  become  sufficiently  opaque,  the  plate  is  well 
washed  and  fixed. 

Some  persons  prefer  citric  acid  to  glacial  acetic  acid. 
The  former  produces  a  bluish-black  deposit,  and  the  latter 
one  of  a  reddish  color,  which  alone  is  capable  of  restraining 
the  action  of  light,  and  thus  of  producing  vigorous  and  bril- 
liant prints.  Citric  acid,  however,  on  a  tour  is  more  con- 
venient, one  grain  being  equivalent  in  working  properties  to 
twenty  of  the  glacial  acetic  acid. 

Fixing  and  Washing  the  Negative. 
The  plate,  already  thoroughly  washed,  is  immersed  in  a 
saturated  solution  of  hyposulphite  of  soda,  where  it  is  al- 
lowed to  remain  until  all  the  unaltered  iodides  and  bromides 
are  removed.  The  intensity  of  the  picture  is  not  at  all  de- 
teriorated by  this  solution.  If  the  plate  has  not  received 
any  substratum,  the  utmost  care  is  now  required  in  finally 
washing  it,  lest  the  film  slide  off.  The  negative  is  allowed 
to  drain  and  is  then  dried  either  spontaneously  or  by  artifi- 
cial heat.  If  the  film  should  show  any  signs  of  splitting  up, 
a  solution  of  gum-water  is  poured  upon  it  as  soon  as  the 
plate  has  drained,  and  after  this  precaution  the  negative  is 
allowed  to  dry. 

'Varnishing  the  Negative. 
A  spirit  lac  varnish  appears  to  be  the  best  adapted  for 
negatives  ;  it  is  prepared  by  dissolving  shell  lac  in  absolute 
alcohol.  The  plate  is  gently  warmed  over  the  stove  or 
lamp,  and  then  coated  with  varnish  as  with  collodion.  After 
the  excess  of  varnish  has  drained  off,  the  plate  is  again 
placed  over  the  stove  or  lamp  until  the  varnish  is  perfectly 
dry.    The  negative  is  now  finished. 

Dry  Collodion — Raisin  Process. 

BY  DR.  SCNAUSS. 

Preparation  of  the  Collodion. 

Fill  a  large  bottle  two  thirds  full  wTith  carded  pyroxy- 
line,  pour  in  a  little  alcohol,  sp.  gr.  .835,  and  shake  the 


THE  RAISIN  PROCESS. 


mixture.  The  pyroxyline  diminishes  considerably  in  vol- 
ume by  this  proceeding.  Ether  is  now  poured  in  so  as  to 
fill  the  bottle  two  thirds  full,  and  the  remaining  one  third 
is  filled  with  absolute  alcohol.  Shake  the  mixture  and 
set  it  aside  for  several  weeks.  The  clear  supernatant  plain 
collodion  is  decanted,  and  diluted  with  a  mixture  of  equal 
volumes  of  ether  and  alcohol.  In  summer  more  alcohol 
than  ether  is  employed.  Judgment  and  experience  must 
decide  when  the  collodion  has  the  requisite  consistence ;  it 
must  not  be  too  thin,  on  the  one  side,  nor  too  thick  to  pre- 
vent it  flowing  without  furrows.  If  it  is  not  thick  enough, 
more  pyroxyline  must  be  added. 

The  bromo-iodizing  solution  is  prepared  in  the  following 
manner : 

Iodide  of  ammonium,  4  drachms. 

Iodide  of  cadmium,  2  drachms. 

Bromide  of  cadmium,  1  drachm. 

Alcohol,  spec,  grav.,  .835,   40  drachms. 

This  solution  may  be  prepared  a  week  before  it  is  re- 
quired to  be  used.  It  is  filtered  through  paper  moistened 
with  alcohol.  A  sufficient  quantity  of  this  solution  is  added 
to  the  plain  collodion  so  as  to  produce  in  the  silver  bath  a 
fine  white  film.  The  bromo-iodized  collodion  is  allowed  to 
settle  and  ripen  for  a  few  days  ;  it  becomes  very  clear  and 
yellow. 


Shake  the  mixture  well,  and  then  expose  it  to  the  direct 
rays  of  the  sun  for  a  number  of  hours.  A  negative  is  now 
prepared  by  the  wet  process  with  the  collodion,  the  silver 
bath,  and  the  ordinary  developers.  If  the  image  appears 
vigorous  and  free  from  fogging,  the  solutions  are  in  a  good 
condition ;  if  otherwise,  add  a  few  drops  of  acetic  acid  to 
the  silver  bath. 


The  Silver  Bath. 


Nitrate  of  silver,    .  . 
Distilled  water,    .    .  . 
Bromo-iodizing  solution, 


.    .    30  drachms. 

360  drachms, 
from  3  to  5  drops. 


Alkaline  Developer. 
Prepare  the  following  solutions : 

No.  1.  Dilute  Alcohol. 

Alcohol,  

Distilled  water,  


18  drachms. 
30  drachms. 


THE  RAISIN  PROCESS. 


375 


No.  2.  Carbonate  of  Ammonia  Solution. 

Dilute  alcohol,  No.  1,  6  drachms. 

Carbonate  of  ammonia,  1  drachm. 

No.  3.  Pyrogallic  Acid  Solution. 

Pyrogallic  acid,  1  drachm. 

Absolute  alcohol,   15  drachms. 

The  latter  solution  will  keep  a  long  time  ;  it  becomes 
red,  but  produces  no  deposit. 

No.  4.  Aqueous  Pyrogallic  Acid  Solution. 

Dilute  alcohol,  No.  1,  4  drachms. 

Pyrogallic  acid  solution,  No.  3,   6  drops. 

No.  5.  Gitro-nitrate  of  Silver. 

Nitrate  of  silver,  20  grains. 

Citric  acid,  20  grains. 

Water,  16  drachms. 

The  alkaline  developer  is  especially  adapted  for  winter 
operations ;  in  summer  the  following  acid  developer  will 
be  found  more  simple  : 

Acid  Developer. 

Pyrogallic  acid,  5  grains. 

Distilled  water,  5  ounces. 

Formic  acid,  1  drachm. 

Alcohol,  15  minims. 

The  exposed  plate  is  previously  flowed  with  the  dilute 
alcohol,  No.  1,  and  then  washed  until  the  surface  appear 
uniformly  moist ;  a  sufficient  quantity  of  the  preceding  acid 
developer  is  then  poured  upon  the  plate,  and  moved  about 
awhile  ;  it  is  then  poured  back  into  a  vial,  and  a  few  drops 
of  the  citro-nitrate  of  silver  are  added.  The  mixture  being 
well  shaken,  is  again  poured  upon  the  plate  and  kept  in 
motion  until  the  picture  is  well  out. 

The  ordinary  developer  of  the  double  sulphate  of  iron 
and  ammonia  may  be  used,  and  with  advantage,  in  the  de- 
velopment of  dry  plates ;  only  in  this  case  the  plate  is  first 
immersed  for  a  few  seconds  in  an  acid  silver  bath,  drained, 
and  then  flowed  with  the  developer. 

Preservative  Solution. 

One  ounce  of  large  raisins  are  boiled  in  ten  ounces  of 
distilled  water ;  the  decoction  is  then  put  aside  to  cool, 


376 


THE  RAISIN  PROCESS. 


after  which  it  is  filtered  and  is  ready  for  use.  A  few  drops 
of  acetic  acid  will  increase  its  keeping  properties. 

Preparation  of  the  Raisin  Plates. 

The  plates  are  to  be  thoroughly  cleaned  and  polished  in 
the  usual  way,  the  edges  having  been  previously  roughened 
by  grinding  on  a  grindstone.  If  a  substratum  of  gelatine 
is  employed,  four  grains  of  gelatine  are  first  soaked  and 
then  dissolved  by  heat  in  four  ounces  of  water ;  the  gela- 
tine solution  is  filtered  while  hot ;  and  to  the  filtered  solu- 
tion a  drachm  of  alcohol  is  added.  With  this  solution  each 
plate  is  coated  in  the  usual  way,  and  set  aside  to  dry.  If 
the  edges  of  the  plates  are  well  roughened  and  the  surfaces 
thoroughly  cleaned,  the  substratum  is  not  necessary. 

The  next  operation  is  to  coat  the  plates  with  the  bromo- 
iodized  collodion,  and  to  sensitize  the  collodion  film  in  the 
silver  bath  in  the  usual  manner.  The  plates  are  then  re- 
moved from  the  silver  bath  and  placed,  collodion-side  up- 
ward, in  a  large,  clean  vessel  of  distilled  water,  and  fre- 
quently moved.  In  five  minutes  each  plate  is  taken  out, 
well  drained,  and  then  flowed  three  times  in  succession  with 
fresh  portions  of  the  raisin  solution,  which  must  be  kept 
carefully  in  motion  so  as  to  cover  the  whole  of  the  plate 
uniformly.  The  plate  is  finally  allowed  to  drain,  and  is 
then  put  away  in  a  dry,  dark  place  to  dry  spontaneously. 

The  depth  of  intensity  of  these  plates  varies  according 
to  the  intensity  of  light  as  well  as  the  nature  of  the  devel- 
opment, the  alkaline  developer  requiring  the  shortest  ex- 
posure, (twenty  seconds  being  about  sufficient  with  a  pair 
of  landscape  stereoscopic  lenses  and  a  good  light ;)  the  or- 
dinary pyrogallic  acid  developer  requires  the  longest  expo- 
sure. The  iron  developer,  in  point  of  sensitiveness,  stands 
next  to  the  alkaline  developer,  and  finally,  close  to  this,  the 
formico-pyrogallic  acid  developer  above  given. 

Mode  of  Development. 

Cover  the  exposed  plate  with  the  dilute  alcohol,  No.  1, 
pour  off  the  alcohol  and  wash  the  film  until  it  is  uniformly 
moist.  Now  take  a  sufficient  quantity  of  the  solution  of 
carbonate  of  ammonia,  mixed  with  one  fourth  its  volume 
of  the  pyrogallic  acid  solution,  No.  3.  Pour  this  mixture 
over  the  plate  and  keep  it  in  motion  until  the  image  is  tho- 
roughly developed.  The  image  at  this  stage  is  very  thin 
and  has  to  be  intensified.  Wash  the  film  thoroughly,  and 
then  intensify  the  negative  with  a  mixture  of  a  sufficient 


A  RELIABLE  TANNIN  PROCESS. 


377 


quantity  of  N"o.  4,  and  a  few  drops  of  No.  5.  To  prevent 
fogging,  when  there  is  reason  to  expect  it,  add  plain  citric 
acid  solution. 


Use  the  best  glass  plates  you  can  procure,  free  from  flaws, 
flat  and  colorless,  grind  or  file  the  edges  ;  and,  whether 
they  have  been  used  before  or  not,  immerse  them  for  a 
number  of  hours  in  the  chromic  acid  bath,  which  is  pre- 
pared as  follows  : 

Bichromate  of  potassa,  2  ounces. 

Sulphuric  acid,  2  ounces. 

Water,  20  ounces. 

When  the  plates  are  taken  out,  allow  them  to  drain,  and 
then  wash  them  at  the  tap  thoroughly,  and  rub  the  surface 
while  they  are  being  washed  with  a  clean  nail-brush,  which 
must  be  kept  and  used  for  this  purpose  alone.  Each  plate, 
while  still  wet,  is  coated  with  the  following  solution  of 
albumen  : 

White  of  egg,  (already  clear  after  beating,).    .    .  1  ounce. 


This  solution  of  albumen  must  be  filtered  before  use 
through  moist  paper.  Cover  the  plate  uniformly  with  the 
solution,  and  see  invariably  that  the  surface  is  free  from 
particles  and  bubbles.  Begin  again  with  the  plate,  where 
the  film  is  thus  defective.  The  plates,  as  they  are  coated 
with  albumen,  are  reared  on  the  drying  rack  in  a  clean, 
quiet  place  where  there  is  neither  dust  nor  draught  of  air. 

A  solution  of  India-rubber  is  sometimes  used  instead  of 
that  of  albumen  for  the  substratum.  The  solution  is  made 
as  follows  : 

Sheet  India-rubber,  2  grains. 

Benzole,  2  ounces. 

Cut  the  India-rubber  into  small  narrow  strips  to  facilitate 
the  solvent  action  of  the  benzole,  and  set  the  mixture  aside 
in  a  stoppered  bottle  for  a  day  or  two.  The  solution  is 
finally  filtered  two  or  three  times  through  fresh  filtering 
paper ;  it  is  then  ready  for  use. 

The  plates,  when  properly  cleaned  and  polished,  are  first 
gently  warmed  over  the  stove  or  a  flame,  allowed  to  cool, 
and  then  coated  with  the  India-rubber  solution  in  the  same 


A  Reliable  Tannin  Process. 


Water,  . 
Ammonia, 


6  ounces. 
1  drachm. 


378 


A  RELIABLE  TANNIN  PROCESS. 


manner  as  with  collodion ;  after  draining,  they  are  again 
warmed  over  the  stove  and  finally  stored  away  for  use. 

To  coat  plates  with  the  latter  solution  is  a  much  easier 
operation  than  with  the  albumen  solution,  and  the  plates 
are  sooner  ready  for  the  next  operation;  still,  most  opera- 
tors will  prefer  the  former  solution,  because  they  are  familiar 
with  its  use. 

Coating  the  Plates  with  Collodion, 

The  collodion  for  dry  plates  is  prepared  as  follows,  al- 
though almost  any  other  good  bromo-iodized  collodion 
would  serve  the  purpose  : 

Collodion  for  Tannin  Plates. 


Alcohol,  10  ounces. 

Ether,  10  ounces. 

Pyroxyline,  120  grains. 

Bromide  of  cadmium,  100  grains. 

Iodide  of  ammonium,  60  grains. 


Prepare  this  collodion  in  the  usual  way,  and,  when  the 
cotton  and  the  salts  are  thoroughly  dissolved,  filter  the  so- 
lution and  set  it  aside  a  day  or  two.  It  may,  however,  be 
used  immediately ;  but  cadmium  collodions  seem  to  be  more 
efficacious  after  they  have  been  prepared  a  day  or  two. 

The  plates  are  coated  with  the  collodion  in  the  usual 
way.  Previously  to  flowing  the  plate,  however,  the  albu- 
menized  plates  are  held  over  a  flame,  the  film  being  up- 
ward, and  are  kept  in  motion  for  a  moment  until  the  mois- 
ture in  the  albumen  has  evaporated.  They  are  then  allowed 
to  cool,  when  they  are  ready  to  be  coated  with  the  collodion. 
As  soon  as  the  film  has  sufficiently  set,  the  plate  is  immersed 
in  the  silver  bath,  and  retained  there  until  the  film  assumes 
a  uniform  cream  color. 

Silver  Bath  for  Tannin  Plates. 

Pure  crystallized  nitrate  of  siiver,  3  ounces. 

Distilled  water,  24  ounces. 

Nitric  acid,  6  minims. 

To  twelve  ounces  of  this  solution  add  a  drachm  of  the 
bromo-iodized  collodion ;  shake  the  mixture  well,  filter  it, 
and  then  add  it  to  the  remaining  twelve  ounces.  The  bath 
is  then  ready  for  use. 

As  soon  as  the  collodion  film  is  sufficiently  sensitized,  that 
is,  has  no  tinge  of  blueness  about  it,  take  it  out  of  the  bath, 


A  RELIABLE  TANNIN  PROCESS. 


379 


let  it  drain,  and  then  place  it  in  a  bath  of  distilled  water  until 
the  oil  marks  have  disappeared.  From  this  bath  it  is  re- 
moved to  the  second  bath,  which  contains  the  following 
solution : 


The  plate  is  kept  in  the  bromide  bath  about  a  minute. 

The  bromide  bath  requires  strengthening  from  time  to 
time,  as  also  filtering,  in  order  to  remove  the  bromide  of 
silver  which  is  formed  by  the  removal  of  the  unaltered  ni- 
trate of  silver  in  the  collodion  film  ;  with  these  occasional 
manipulations  the  bath  will  keep  for  an  indefinite  time. 

The  plate  is  taken  out  of  the  bromide  bath  and  immersed 
again  in  a  bath  of  distilled  water,  in  which  it  is  left  a  min- 
ute or  two ;  from  this  bath  the  plate  is  removed  and  placed 
on  the  rack  to  drain  for  a  couple  of  minutes. 

The  operator  will  naturally  comprehend  that  all  these 
operations  are  performed  in  the  dark,  or  non-actinic  room. 
Be  careful,  if  yellow  or  orange-colored  light  is  admitted,  that 
this  light  is  non-actinic,  because  it  is  a  disagreeable  piece 
of  business  to  fail  with  dry  plates  after  all  the  trouble  that 
is  bestowed  upon  them ;  and  frequently  the  failure  may  be 
traced  to  actinic  rays  exercising  their  influence  during  tho 
preparation  of  the  plates. 

Wipe  the  back  of  each  plate  carefully  after  it  has  drainec 
awhile,  and  immerse  it  in  a  bath  containing  the  following 
solution  of  tannin  : 

Tannin,   300  grains. 

Loaf  sugar,   300  grains. 

Water,  20  ounces. 

The  tannin  and  sugar  are  dissolved  in  the  water,  being  all 
placed  in  a  large  stoppered  bottle  holding  about  twenty-four 
ounces.  Shake  the  mixture  occasionally  until  the  solution 
is  complete.  The  letter  is  filtered  through  a  moist  filter. 
Now  add  to  the  solution  an  ounce  of  alcohol.  Pour  the 
solution  back  again  into  the  stock  bottle  every  time  the 
operation  of  sensitizing  a  given  quantity  of  plates  is  fin- 
ished ;  and  keep  the  bottle  well  corked.  Filter  the  solu- 
tion when  necessary. 

The  plates  are  left  in  this  bath  two  or  three  minutes,  and 
then  taken  out  and  allowed  to  drain.  Finally  they  are 
stored  away  in  the  drying  chamber  to  dry  either  sponta- 
neously or  by  artificial  heat, 


Bromide  of  cadmium, 
Water,  .... 


100  grains. 
12  ounces. 


18 


380 


A  RELIABLE  TANNIN  PROCESS. 


Exposure  of  the  Tannin  Plates. 

Considerable  experience  is  required  to  know,  under  given 
circumstances,  the  length  of  exposure  that  would  most 
likely  be  correct.  From  our  own  experience,  an  exposure 
two  or  three  times  longer  than  that  required  by  a  wet  plate 
will  be  necessary,  to  produce  a  good  picture  by  the  tannin 
process,  even  with  the  alkaline  developer.  In  every  case  do 
not  practice  short  exposures,  for  they  generally  either  fail 
altogether,  or  yield  at  the  best  harsh  contrasts,  when  the 
negatives  are  forced  up  to  full  intensity.  A  full  exposure 
produces  full  detail ;  and  an  over-exposed  plate  can  be  con- 
trolled by  the  development.  It  is  true  that  too  long  expo- 
sures will  produce,  if  the  negatives  are  carelessly  managed, 
harsher  contrasts  than  under-exposed  plates.  The  develop- 
ment of  a  dry  plate,  therefore,  has  to  be  carefully  studied. 

Development  of  a  Tannin  Plate. 

The  development  of  a  tannin  plate  is  divisible  into  two 
operations ;  the  first  consists  in  bringing  out  the  picture 
faintly  but  distinctly  in  all  its  details,  with  the  alkaline  so- 
lution ;  the  second  consists  in  rendering  all  the  parts  of  the 
picture  more  intense,  so  as  to  make  it  suitable  for  printing 
from. 

Solutions  required  in  these  two  operations. 


No.  T.  Dilute  Alcohol. 

Alcohol,  2  ounces. 

Water,  •   ....    2  ounces. 

No.  2.  Alkaline  Solution. 

Carbonate  of  Ammonia,  48  grains. 

Water,  6  ounces. 

Two  drachms  of  this  solution  contain  two  grains  of  the 
alkaline  salt. 

No.  3.  Pyrogallic  Acid  Solution. 

Pyrogallic  acid,  48  grains. 

Absolute  alcohol,  1  ounce. 

Ten  minims  of  this  solution  contain  one  grain  of  pyro* 
gallic  acid. 

No.  4.  Nitrate  of  Silver  Solution. 

Nitrate  of  Silver,  20  grains. 

Water,   2  ounces. 


A  RELIABLE  TANNIN  PROCESS. 


381 


No.  5.  Solution  of  Citric  Acid. 


Citrid  acid, 
Water,  . 


2  drachms. 
4  ounces 


No.  6. 


Water, 


1  pint. 


Alkaline  Development — First  Operation. 


As  soon  as  the  plate  is  removed  from  the  plate-holder  or 
changing  box,  in  the  dark-room,  pour  upon  the  film  a  suffi- 
cient quantity  of  dilute  alcohol,  No.  1,  until  the  film  is 
uniformly  covered  with  it ;  then  allow  the  solution  to  flow 
back  again  into  the  vial.  Now  immerse  the  plate  in  a  dish 
of  water  until  the  greasy  appearance  passes  off.  In  the 
mean  while  make  the  following  mixture : 

Alkaline  solution,  No.  2,  2  drachms. 

Water,   1  ounce 

Flow  the  plate  uniformly  with  this  solution,  which  is  im- 
mediately returned  to  the  developing  vial,  and  mixed  with 
three  minims  of  the  alcoholic  pyrogallic  solution.  This  mix- 
ture is  poured  upon  the  plate  and  kept  in  motion.  Soon  the 
image  will  begin  to  appear,  if  the  right  exposure  has  been 
given,  and  will  proceed  until  it  is  complete  in  all  its  detail. 
It  is,  to  be  sure,  but  a  faint  picture ;  but  this  picture  by  the 
second  operation  can  be  made  as  intense  as  the  operator 
may  wish.  Should  it  happen  that  the  picture  appears  with 
great  rapidity  on  the  application  of  the  alkaline  solution, 
pour  the  latter  off  directly  and  wash  the  plate.  Such  a 
rapidity  of  development  indicates  that  the  plate  has  been 
over-exposed,  in  which  case  the  action  of  the  second  ope- 
ration with  the  acid  developer  will  be  sufficient  of  itself  to 
bring  out  the  picture. 

To  Intensify  the  Image — Second  Operation. 

Wash  the  faint  image  gently  at  the  tap,  and  then  pour 
upon  it  the  following  solution: 

Solution  of  citric  acid,  20  minims. 

Water,   4  drachms. 

The  intention  of  this  solution  is  to  remove  all  traces  of  the 
alkali.  Pour  this  solution  off  after  it  has  remained  about  a 
minute,  and  then  flow  the  plate  with  the  following  solution : 


382  russell's  improved  tannin  process. 


Intensifier  —  Citro-nitrate. 

Water,  .    .  4  drachms. 

Pyrogallic  acid,  No.  3,     ....    2  minims. 

Citric  acid,  No.  5,   10  minims.   )  Previously 

Nitrate  of  Silver,  No.  4,   ....    3  minims.   )  mixed. 

Shake  the  mixture  well  up,  and  then  pour  it  upon  the  plate. 
Gradually  the  faint  image  becomes  more  and  more  intense. 
If  the  intensity  increases  too  rapidly,  and  the  lights  begin 
to  fog,  add  more  citric  acid  to  the  intensifier ;  on  the  con- 
trary, if  the  delineations  of  the  picture  are  slow  in  becom- 
ing more  dense,  add  more  of  the  silver  solution.  If  the  in- 
tensifier becomes  red  and  turbid,  throw  it  away  and  prepare 
a  fresh  solution. 

The  picture  when  intensified  by  this  citro-nitrate  of  silver 
solution  becomes  of  a  grayish  black  appearance  ;  but  if  the 
acetic-nitrate  of  silver  were  substituted,  the  picture  has  a 
reddish  tone  ;  and  negatives  thus  prepared  produce  very 
excellent  prints. 

Intensifier — Aceto-nitrate. 

Water,  .4  drachms. 

Pyrogallic  acid,  No.  3,     ....    2  minims. 

Acetic  acid,   15  minims.   )  Previously 

Nitrate  of  silver,  No.  4,  ....    3  minims.   )  mixed. 

Proceed  with  this  intensifier  as  with  the  citro-nitrate, 
only  using  more  acetic  acid  when  fogging  sets  in  instead  of 
citric  acid. 

The  picture  being  now  sufficiently  intense  is  thoroughly 
washed  at  the  tap,  and  then  immersed  in  the  bromide  bath 
for  a  minute.  It  is  again  well  washed  and  fixed  in  a  satu- 
rated solution  of  hyposulphite  of  soda. 

Finally  the  negative  is  again  thoroughly  washed,  then 
dried  and  varnished. 

Major  Russell's  latest  Improvements  in  the  Tannin 

Process. 

Prepare  the  plates  as  already  described  in  the  preceding 
process,  either  with  an  albumen  or  India-rubber  substratum. 
The  collodion  recommended  by  the  Major  is  as  follows: 


Alcohol,  spec,  grav.,  .810,  5  ounces. 

Ether,    5  ounces. 

Pyroxyline,  50  grains. 

Bromide  of  cadmium,  150  grains. 


russell's  improved  tannin  process. 


383 


This  collodion  contains  only  a  bromide.  The  silver  bath  is 
prepared  as  follows  : 


Place  a  bromized  plate  in  this  bath  for  an  hour  or  two, 
and  then  filter  it.  The  bath  is  now  ready  for  use.  Coat  a 
prepared  plate  with  the  bromized  collodion,  and  immerse  it 
in  the  silver  solution  in  the  usual  manner.  The  plate,  when 
the  film  is  quite  creamlike  in  color,  is  removed  from  the  sil- 
ver solution  and  placed  in  a  bath  of  distilled  water,  where 
it  remains  until  the  greasiness  disappears.  It  is  then  placed 
in  a  second  bath  of  distilled  water  for  a  minute  or  two. 
From  this  the  plate  is  removed  to  a  third  bath  containing 
the  following  solution : 

Albumen,   24  minims. 

Distilled  water,   12  ounces. 

Iodide  of  cadmium,   8  grains. 

Bromide  of  cadmium,    1  drachm. 

Camphor,   1  drachm. 

The  plate  remains  in  this  bath  a  minute  or  two.  The  ob- 
ject of  this  bath  is  twofold;  firstly,  the  albumen  acts  like 
sizing  to  paper,  by  rendering  the  collodion  film  less  porous 
or  permeable  to  fluids  than  it  was  before ;  secondly,  the 
cadmium  salts  remove  every  trace  of  unaltered  nitrate  of 
silver.  The  iodide  of  cadmium,  too,  is  intended  to  intro- 
duce a  trace  of  iodide  of  silver  into  the  film,  which  is  in 
some  way  regarded  by  the  author  as  beneficial. 

From  the  bromide  bath  the  plate  is  removed  to  a  fourth 
bath  of  common  spring-water,  and  thence  to  the  bath  con- 
taining the  tannin  solution,  where  it  remains  about  one 
minute. 

The  plate  is  finally  taken  out,  thoroughly  washed  at  the 
tap,  and  then  set  away  in  a  convenient  place  to  dry. 


As  soon  as  the  plates  are  dry,  the  Major  paints  the  backs 
of  the  plates  with  an  orange-colored  paint,  mixed  up  with 
gum  or  dextrine  and  a  little  glycerine.  The  paint  is  laid 
on  thickly  with  a  broad  brush,  and  after  exposure  it  may 
be  peeled  off  with  a  fine  pallet  knife,  and  dissolved  again 
in  water  for  future  use.  The  object  of  this  film  of  orange- 
colored  paint  on  the  back  of  the  glass  is  to  prevent  all  the 
effects  of  reflections  from  the  back  surface  of  the  glass, 


Nitrate  of  silver, 
Distilled  water, 
Nitric  acid, 


.  2  ounces. 
14  ounces. 
14  minims. 


Exposure. 


384 


russell's  improved  tannin  process. 


called  blurring.  The  author  is  very  strong  in  the  recom« 
mendation  of  this  course.  When  the  paint  is  dry,  the 
plates  are  ready  for  exposure. 

After  exposure,  the  plates  are  first  covered  uniformly 
with  the  dilute  alcohol  of  the  preceding  article,  and  then 
immersed  in  a  dish  of  water  and  left  there  until  the  greas- 
iness  has  disappeared. 

The  following  solutions  are  used  in  the  development : 

No.  1.  Pyrogallic  Acid. 


Pyrogallic  acid,   .    16  grains. 

Alcohol,  1  ounce. 

Distilled  water,   1  ounce. 

No.  2.  Carbonate  of  Ammonia. 

Sesqui-carbonate  of  ammonia,  48  grains. 

Distilled  water,  3  ounces. 

No.  3.  Intensifier. 

Bromide  of  potassium,  3  grains. 

Sesqui-carbonate  of  ammonia,  32  grains. 

Water,  1  ounce. 


Take  a  mixture  of  one  drachm  of  the  first  solution,  and 
one  drachm  of  the  second  solution,  shake  it  well  up  ;  this 
is  the  alkaline  developer.  Cover  the  wet  plate  with  this 
solution,  and  keep  the  latter  in  motion  until  the  image  ap- 
pears perfect  in  detail. 

After  the  image  is  thus  brought  out  thoroughly  by  the  al- 
kaline developer,  it  may  be  intensified  by  dropping  into  the 
developer  a  minim  or  two  of  the  intensifier  No.  3.  The 
author  remarks  of  this  intensifier  as  follows :  u  Three 
grains  of  bromide  of  potassium  in  one  ounce  of  the  thirty- 
two  grain  solution  of  carbonate  of  ammonia  will  make  a 
very  good  intensifier,  and  it  may  be  used  to  develop  when 
much  diluted,  instead  of  the  plain  carbonate  of  ammonia 
solution,  when  soluble  salt  enough  has  not  been  left  in  the 
film,  or  when  this  is  the  proper  condition,  after  a  longer  ex- 
posure. This  is  a  good  plan  when  great  vigor  and  bright- 
ness are  more  important  than  sensitiveness.  Using  more 
or  less  bromide  in  the  developer  is  the  best  way  yet  devised 
of  regulating  intensity.  In  this  way  we  are  able — when 
time  of  exposure  is  not  an  object — to  obtain  great  vigor 
under  almost  any  circumstances  ;  such  as  a  very  dull  light. 
In  this  way  also,  plates  prepared  for  instantaneous,  pictures 
will  answer  as  well  as  others  for  any  kind  of  subject." 


MODIFIED  FOTHERGILL  PROCESS. 


Instead  of  using  the  bromide  intensifies  naturally,  the 
ordinary  acid,  pyrogallic  acid,  and  nitrate  of  silver  may 
be  used  as  in  the  preceding  processes. 

Modified  Fothergill  Process. 

The  public  are  indebted  to  Mr.  Ackland,  an  experienced 
photographer,  and  one  who  has  tried  all  the  dry  processes, 
for  the  following  modification  of  the  Fothergill  process. 
The  author  prefers  it  to  all  of  them  ;  and  reliable  judges 
pronounce  the  negatives  taken  by  the  process  irreproacha- 
bly good.  The  plates,  too,  are  said  to-  be  very  sensitive  ; 
and  there  seems  to  be  no  doubt  of  their  keeping  qualities. 

The  collodion  most  suitable  for  this  process  is  the  ordi- 
nary bromo-iodized  used  in  general  by  photographers.  If 
it  be  newly  made,  a  sufficient  quantity  of  tincture  of  iodine 
to  communicate  to  it  the  color  of  sherry  wine  will  be  found 
advantageous  in  preventing  fogginess.  The  only  point  to 
be  attended  to  in  selecting  a  suitable  collodion  is  to  take 
one  which  yields  a  full  creamy  film  in  the  silver  bath,  and 
which  has  no  tendency  to  leave  the  plate  during  washing. 
As  most  of  our  operators  now  use  a  substratum  of  albumen, 
it  will  be  well  to  use  plates  previously  so  coated,  in  order 
to  avoid  all  risk,  in  the  film,  of  slipping  off. 

The  silver-bath  must  have  a  slight  acid  reaction,  and  con- 
tain not  less  than  thirty-five  grains  of  nitrate  of  silver  to  the 
ounce  of  water.  The  author  of  this  modified  process  pre- 
pares the  bath  in  the  following  manner : 

Dissolve  an  ounce  of  re-crystallized  nitrate  of  silver  in 
two  ounces  of  water;  to  this  solution  add  two  drachms  of 
the  bromo-iodized  collodion  intended  to  be  used.  After 
the  mixture  has  been  well  shaken  up,  ten  ounces  more  of 
water  are  added ;  it  is  again  well  shaken  and  then  set  aside 
for  a  few  hours,  after  which  it  is  filtered  for  use.  Such  a 
bath  will  be  found  sufficiently  acid  for  the  purpose. 

Mr.  Ackland  prepares  the  albumen  solution  as  follows : 
Separate  the  yolks  from  the  whites  of  any  number  of  eggs, 
and  to  every  eight  ounces  of  the  albumen  thus  obtained, 
add  twenty  drops  of  glacial  acetic  acid  previously  diluted 
with  one  ounce  of  water.  The  mixture  is  intimately  stirred 
up  with  a  glass  rod,  and  then  set  aside  for  an  hour.  After 
this  it  is  strained  through  coarse  muslin,  and  to  the  strained 
liquid  are  added  thirty  minims  of  concentrated  ammonia. 
This  forms  the  stock  solution  of  albumen,  which  will  keep 
for  an  indefinite  time  in  carefully  stoppered  bottles ;  it  is 


386 


MODIFIED  FOTHERGILL  PROCESS. 


also  limpid,  clear,  and  bright,  and  may  be  filtered  through 
ordinary  filtering-paper  with  facility. 

Besides  the  albumen  solution,  six  others  are  required  in 


the  process. 

Solution  A. 

Prepared  albumen,  4  drachma. 

Concentrated  ammonia,   1  drachm. 

Water,   4  ounces. 

Solution  B. 

Nitrate  of  silver,  8  grains. 

Distilled  water,  4  ounces. 

Dilute  Acetic  Acid, 

Glacial  acetic  acid,  1  drachm. 

Water,  10  ounces. 

Plain  Solution  of  Pyrogalliv  Acid. 

Pyrogallic  acid,  100  grains. 

Absolute  alcohol,  2  ounces. 

Acid  Solution  of  Pyrogallic  Acid. 

Pyrogallic  acid,  .    ,    ,  8  grains. 

Citric  acid,  ,  %  ounces 

Distilled  water,  ,    ,    ,   4  ** 

Acid  Silver  Solution, 

Nitrate  of  silver,   30  grains. 

Citric  acid,   30  " 

Distilled  Water,   1  ounce. 


The  solutions  A  and  B  are  to  be  mixed  in  equal  propor- 
tions for  present  use.  This  mixture  soon  decomposes,  and 
then  produces  foggy  plates. 

Coating  the  Plates  loith  Collodion, 

This  operation  requires  no  instructions  ;  it  is  performed 
in  the  usual  manner,  after  which  the  plate  is  immersed  in 
the  silver  as  soon  as  the  collodion  film  has  properly  set. 
The  film  having  assumed  a  uniformly  cream-color,  it  is  taken 
out  and  kept  moving  about  in  a  tray  of  water  until  the 
greasiness  has  disappeared ;  it  is  then  allowed  to  rest  in  the 
water  while  another  plate  is  coated  and  immersed  in  the 
silver  solution.  Ordinary  well  or  spring-water  may  be  used 
in  this  and  the  subsequent  washings.  The  plate  that  has 
been  soaking  is  now  washed  again  in  several  changes  of 
water  for  the  space  of  two  minutes,  and  finally  flooded 
with  solution  of  common  salt,  formed  by  dissolving  a  table* 


haakman's  fothergill  process. 


387 


spoonful  in  twenty  ounces  of  water.  After  this  solution  has 
remained  on  the  plate  for  about  half  a  minute,  it  is  poured 
off,  and  the  plate  is  washed  carefully  under  the  tap  in  order 
to  remove  every  trace  of  the  salt  solution,  and  is  then 
reared  with  one  corner  on  several  folds  of  blotting-paper, 
and  with  the  other  against  the  wall  to  drain. 

Coating  the  Plates  with  the  Albumen. 

Other  plates  are  prepared  in  like  manner.  Before  the  - 
film  is  dry,  that  is,  while  it  is  uniformly  moist,  each  plate 
is  flowed  with  the  mixture  of  A  and  B  ;  this  solution  is 
poured  away,  and  fresh  solution  is  poured  on  and  off  seve- 
ral times  ;  the  plate  is  then  reared  up  as  before  on  blotting- 
paper,  and  allowed  to  drain,  but  not  to  dry.  Half  a  dozen 
plates  may  thus  be  prepared  before  the  next  operation  is 
commenced  with,  that  is,  before  the  plates  begin  to  get  dry. 

Immersing  the  Plates  in  Acetic  Acid. 

The  plates  that  have  been  albumenized  and  drained  are 
immersed  in  a  bath  of  the  dilute  acetic  acid  for  the  space  of  a 
minute  or  so  ;  they  are  again  washed  thoroughly  for  half  a 
minute,  then  allowed  to  drain  and  dry  spontaneously  in  any 
convenient  drying-chamber. 

A  Second  Modification  of  the  Fothergill  Process. 
By  Mr.  Haakman. 

The  plates  are  prepared  as  before  up  to  the  albumenizing. 
The  albumen  solution  contains  a  few  drops  of  ammonia  to 
every  five  ounces.  After  beating  together,  it  is  left  to  set- 
tle over  night,  then  filtered  through  wet  sponge  and  pre- 
served in  combination  with  a  piece  of  camphor  for  future 
use.  With  this  solution  the  collodionized  and  washed  film 
is  coated  carefully  ;  the  first  portion  being  allowed  to  flow 
forward,  but  not  backward,  and  then  thrown  away.  The 
plate  is  then  flowed  once  more  with  a  fresh  portion  of  the 
albumen,  and  drained.  The  back  of  the  plate  is  dried  witli 
a  pad  of  blotting-paper.  The  plate  is  now  ready  for  the 
next  operation,  which  is  the  essential  modification. 

Washing  the  Plate  in  Hot  Water. 

Take  a  clean  tray  about  twice  as  large  as  the  plate,  and 
pour  sufficient  boiling  water  into  it  to  cover  the  bottom 
to  the  depth  of  a  quarter  of  an  inch  ;  then  tilt  the  tray, 
and  place  the  albumenized  plate  on  the  dry  end,  the  film 


388 


haakman's  fothergill  process. 


being  upwards.  By  a  quick  but  gentle  motion,  the  plate 
can  be  covered  uniformly  with  the  hot  water ;  this  is  kept 
in  motion  for  half  a  minute,  when  the  plate  is  taken  out, 
and  the  back  being  again  wiped  with  blotting-paper,  it  is 
put  away  to  dry  in  the  drying-chamber. 

Developer. 

Pyrogallic  acid   3  grains. 

Water,    ...   1  ounce. 

Citric  acid,  2  grains. 

The  exposed  plate  is  washed  under  the  tap  before  devel- 
opment ;  it  is  then  flowed  with  a  sufficient  quantity  of  py- 
rogallic solution,  which  being  poured  back  into  a  develop- 
ing vial,  is  strengthened  with  a  few  drops  of  a  two  per 
cent  nitrate  of  silver  solution.  If  the  development  proceeds, 
although  slowly,  yet  gradually,  add  no  more  of  the  silver- 
solution  ;  on  the  contrary,  more  of  this  solution  is  to  be 
added  if  the  picture  ceases  to  proceed  in  development. 

The  author  gives  a  second  mode  of  development,  as  fol- 
lows.   Prepare  the  two  following  solutions  : 


Solution  A. 

Gallic  acid,   ,    .      V2  grains. 

Boiling  water,  4  drachms. 

Allow  it  to  cool,  then  filter,  and  add  twelve  minims  of 
acetic  acid. 

Solution  B. 

Acetate  of  lead,  5  grains,     )  To  be  filtered  after 

Water,  4  drachms.  )  solution. 


The  plate,  after  exposure,  is  wetted  with  water,  and  then 
flowed  with  solution  A.  The  solution  is  then  poured  back 
into  the  developing  vial  containing  a  few  drops  of  a  two 
per  cent  nitrate  of  silver  solution,  and  a  few  drops  of  the 
solution  B.  A  precipitate  is  formed,  which  is  not  regarded. 
Stir  the  solution  and  pour  it  quickly  over  the  plate.  Gen- 
erally the  picture  appears  at  once  in  all  its  details,  and  fre- 
quently, though  not  always,  of  the  necessary  strength. 

If  found  necessary,  the  plate,  after  washing,  is  intensified 
with  pyrogallic  acid  and  silver. 


THE  COLLODIO-BROMIDE  PROCESS. 


389 


Photography  without  a  Nitrate  of  Silver  Bath. 

Wet  and  Dry  Negative  Processes  with  Collodio-bromide 
of  Silver,  by  jB.  J.  Sayce. 

The  author  of  this  process  has  prepared  a  large  number 
of  plates  by  it  with  unvarying  certainty  and  cleanliness. 
There  can  be  no  doubt  as  to  its  practicability,  and  the 
beautiful  results  to  be  obtained  by  it. 

Preparation  of  the  Collodion. 

The  collodion  which  the  author  has  used  for  now  three 
years,  contains  only  bromides,  as  the  reader  will  see. 

Pbrmula. 


Ether,  1  ounce. 

Alcohol,  1  " 

Bromide  of  cadmium,  6  grains. 

Bromide  of  ammonium,  2  " 

Pyroxyline,  6  " 


Prepare  as  much  as  may  be  required  for  a  given  opera- 
tion, and  when  mixed,  set  it  aside  for  a  week  and  filter. 

The  collodion  is  now  ready  for  being  sensitized.  Take 
twenty-four  grains  of  crystallized  nitrate  of  silver,  and  re- 
duce it  to  a  fine  powder  in  a  mortar  ;  then  add  a  drop  or 
two  of  water,  that  is,  sufficient  to  convert  the  powder  into 
a  pulp.  This  pulp  is  finally  mixed  with  the  collodion  in  the 
dark  room,  and  stirred  about  with  a  glass  rod  until  the 
mixture  is  quite  uniform.  The  latter  is  then  poured  into  a 
vial  for  its  reception.  The  mixture  is  well  shaken,  and  then 
set  aside  to  settle  for  an  hour  or  two.  At  the  end  of  this 
time  the  clear  portions  are  decanted  into  a  vial  for  present 
use. 

Use  of  the  Collodio-bromide  in  the  Wet  Process. 

The  plates,  after  cleaning,  are  coated  with  either  the  al- 
bumen or  India-rubber  solution,  as  already  recommended  in 
the  preceding  processes,  or  the  edges  alone  may  be  var- 
nished all  round  to  the  depth  of  one  eighth  of  an  inch  on 
the  flat  surface,  to  be  coated  with  the  collodion.  This  sur- 
face is  then  coated  with  the  collodio-bromide  in  the  usual 
manner.  After  the  film  has  set,  the  plate  is  placed  in  a 
dish  of  water  Until  the  greasiness  has  disappeared  ;  warm 
water  is  to  be  preferred,  because  the  film  is  more  sensitive 
after  treatment  with  it. 


390 


THE  COLLODIO-BROMIDE  PROCESS. 


As  soon  as  the  water  flows  uniformly  over  the  surface  of 
the  collodio-bromide  film,  the  plate  is  removed  from  the 
water-bath,  is  allowed  to  drain,  and  the  back  of  the  plate 
is  wiped  with  a  pad  of  blotting-paper.  It  is  then  placed  in 
the  plate-holder  and  exposed. 

The  exposure  is  a  little  longer  than  is  required  by  the 
ordinary  wet  collodion  plate.  After  exposure,  a  little  water 
is  poured  over  the  film,  and  afterward  the  developer. 


To  three  drachms  of  this  solution,  add  two  drops  of  a 
twenty-grain  solution  of  nitrate  of  silver.  This  solution  is 
well  shaken,  and  then  poured  over  the  moist  film.  The  im- 
age appears  quickly,  and  in  all  respects  is  similar  to  that 
which  is  produced  by  the  ordinary  wet  process.  The  ope- 
rator will  soon  be  enabled  to  regulate  the  time  of  exposure 
from  the  nature  of  the  development.  If  the  picture  is  not 
sufficiently  intense,  it  may  be  rendered  so  by  any  of  the 
common  modes  of  re-development  or  intensification. 

The  developed  image  is  fixed  in  a  solution  of  cyanide  of 
potassium,  containing  twenty  grains  to  the  ounce  of  water. 

Use  of  the  Collodio-bromide  in  the  Preparation  of 
Tannin  Plates, 

The  glass  plates  are  prepared  as  just  described  for  the 
wet  process  ;  they  are  also  coated  in  the  same  manner  with 
the  collodio-bromide.  As  soon  as  thus  coated  with  the  col- 
lodion, each  plate  is  reared  away  in  a  pail  of  water,  until 
the  proper  quantity  has  been  so  far  prepared. 

The  number  of  plates  being  completed,  they  are  placed 
in  rotation  in  a  dish  of  hot  water,  as  hot  as  the  hand,  can 
bear,  for  about  thirty  seconds,  and  then  removed  and  im- 
mersed in  the  tannin  solution,  containing  fifteen  grains  to 
the  ounce  of  water,  and  well  filtered,  or  into  a  bath  of  the 
following  solution,  which  the  author  finds  superior  to  the  or- 
dinary tannin  solution  : 


Developer. 


Protosulphate  of  iron, 
Glacial  acetic  acid,  . 
Water,  


25  grains. 
25  minims. 
1  ounce. 


Mr.  Verity's  Tannin  Bath. 


Tannin,   .  . 
Gallic  acid, 
"Water, 
Grape  sugar, 
Alcohol, 


,  10  ounces. 

50  grains. 
100  minims. 


100  grains. 


50  " 


THE  COLLODIOBROMIDE  PROCESS. 


391 


Dissolve  the  tannin  in  a  portion  of  the  water,  and  filter. 
The  gallic  acid  is  dissolved  in  another  portion  by  the  aid 
of  heat,  and  is  likewise  filtered.  The  two  solutions  are 
mixed  together,  and  then  the  grape-sugar  is  added.  After 
this  is  dissolved,  the  mixture  is  again  filtered.  The  alcohol 
is  finally  added  ;  the  bath  is  now  ready  for  use. 

The  plates  are  kept  in  the  tannin  solution  three  minutes ; 
they  are  then  taken  out,  drained  and  dried  evenly  and 
quickly  in  any  convenient  and  suitable  manner. 

The  exposure  of  these  dry  plates  is  about  half  the  time 
of  ordinary  tannin  plates  with  bromo-iodized  collodion.  If 
the  exposure  is  properly  timed,  very  little  intensification  is 
necessary. 

Development  of  the  Collodio-bromide  Plate. 
Prepare,  in  the  first  place,  the  following  solutions : 
No.  1.  Dilute  Alcohol. 

Alcohol,   2  ounces. 

Water,  2  " 

No.  2.  Carbonate  of  Ammonia  Solution. 

Carbonate  of  ammonia,  40  grains. 

Water,  20  ounces. 

No.  3.  Pyrogallic  Acid  Solution. 

Pyrogallic  acid,  96  grains. 

Absolute  alcohol,   .1  ounce. 

No.  4.  Solution  of  Bromide  of  Potassium. 

Bromide  of  potassium,    .  10  grains. 

Water,   1  ounce. 

No.  5.  Acid  Nitrate  of  Silver. 

Nitrate  of  silver,  30  grains. 

Citric  acid,  15  " 

Distilled  water,  1  ounce. 

The  plate,  after  exposure  and  immediately  before  develop- 
ment, is  flowed  with  a  sufficient  quantity  of  the  dilute  alco- 
hol, No.  1.  The  excess  is  poured  back  again  into  the  vial 
for  future  use.  After  this  operation  the  plate  is  immersed 
in  a  dish  of  water,  and  kept  there  until  the  greasy  appear- 
ance has  vanished. 

When  the  water  flows  easily  over  the  plate,  it  is  flowed 
*  with  the  following  solution  : 


392 


THE  PORCELAIN  PICTURE. 


Alkaline  Developer. 

A  sufficient  quantity  of  No.  2. 

Two  or  three  drops  of  No.  3. 

Two  drops  of  No.  4. 

Shake  the  mixture  and  pour  it  upon  the  plate,  and  keep  it 
in  motion  so  as  to  avoid  unequal  development.  The  image 
will  soon  appear,  if  the  exposure  has  been  right.  Continue 
to  develop  until  all  the  detail  is  out,  and  as  long  as  there  is 
no  fogging  on  the  shadows. 

The  plate  is  now  thoroughly  washed  in  water,  and  after- 
ward flowed  with  dilute  acid,  (glacial  acetic,  two  drops ; 
water  one  ounce ;)  finally  it  is  again  washed. 

If  the  picture  requires  intensification,  prepare  the  follow- 
ing solution : 

Intensifier. 

Water,  2  drachms. 

Three  drops  of  No.  3. 

Three  drops  of  No.  5. 

Shake  the  mixture,  then  pour  it  upon  the  plate,  and  keep  it 
in  motion  until  the  proper  degree  of  intensity  is  obtained. 
If  the  mixture  becomes  turbid  or  highly  colored,  prepare  a 
fresh  solution,  and  continue  the  operation.  Finally,  when 
the  image  is  sufficiently  dense,  the  plate  is  thoroughly 
washed  and  then  fixed  in  the  solution  of  cyanide  of  potas- 
sium of  the  same  strength  as  for  wet  plates. 

Strong  cyanide  answers  better  than  a  weak  solution,  as 
the  film  is  apt  to  split  up  and  slide  off  with  a  weak  solution. 
Still,  if  the  plates  have  previously  been  coated  with  albu- 
men, etc.,  such  an  accident  will  not  happen. 

Porcelain  Pictures,  or  Opaltype. 

This  is  a  very  pleasing  picture,  when  properly  executed 
with  the  proper  amount  of  detail,  and  the  regular  gradation 
of  lights,  shades,  and  middle  tones  ;  it  is,  as  may  be  implied 
from  its  name,  a  photograph  on  white  or  opalescent  glass. 
There  are  several  methods  of  preparing  this  delightful  pho- 
tograph. We  shall  describe  those  which  we  practice  suc- 
cessfully ourselves.  The  first  is  effected  by  means  of  the 
camera,  and  the  second  by  the  dry  process. 

To  take  Opal  Pictures  by  means  of  the  Camera. 

Select  the  flattest  pieces  of  porcelain  glass  for  photographic 
purposes,  and  such  as  are  quite  free  from  flaws  of  every  kind; 


THE  PORCELAIN  PICTURE. 


393 


if  by  accident  you  find  a  number  of  opal  plates  that  are  con- 
cave on  one  side  and  convex  on  the  other,  (and  you  will  cer- 
tainly find  such,  if  you  do  not  make  your  own  selection,) 
you  need  not  be  particularly  alarmed  on  this  account ;  for, 
by  means  of  the  process  about  to  be  described,  such  plates 
can  easily  be  used  up,  taking  care  to  place  the  picture  on 
the  concave  surface. 

Preparation  of  the  Opal  Plates. 

Grind  or  file  the  edges  of  porcelain  glass  as  you  would 
those  of  your  negative  plates.  Clean  and  polish  them,  too, 
precisely  in  the  same  way.  In  this  process  it  is  particularly 
advisable  to  coat  one  surface  of  each  plate  (the  concave 
surface  if  the  plate  is  curved)  with  a  substratum  of  albumen ; 
the  albuminous  solution  is  prepared  as  follows  : 

Separate  the  whites  from  two  or  three  eggs  carefully,  and 
for  each  ounce  of  the  albumen  take  eight  ounces  of  distilled 
or  rain-water,  and  one  drachm  of  ammonia.  Stir  the  mix- 
ture with  an  egg-beater,  and  when  it  is  entirely  reduced  to 
froth,  set  it  aside  to  settle.  In  the  course  of  twenty-four 
hours  the  albumen  will  have  settled,  and  may  easily  be 
separated  from  the  hardened  or  insoluble  crust  by  decanta- 
tion.  It  is  now  filtered  through  a  piece  of  clean  and  moist 
sponge,  and  is  then  ready  for  use. 

The  plates,  when  clean,  may  be  left  in  a  dish  of  perfectly 
pure  water.  Each  one  is  then  taken,  allowed  to  drain  a 
moment,  and  then  coated  with  the  filtered  albumen  in  the 
same  manner  as  with  collodion.  Caution  is  required,  how- 
ever, not  to  let  the  albumen  fall  from  a  great  height,  but  to 
place  the  mouth  of  the  vial  which  contains  it  just  in  contact 
with  the  surface  of  the  plate  to  be  coated.  This  surface 
being  moist,  and  not  greasy,  the  albumen  will  easily  spread, 
and,  driving  the  moisture  before  it,  will  soon  cover  the  whole 
plate.  If  there  are  any  bubbles  or  any  insoluble  and  pro- 
tuberant particles  on  the  film,  it  will  be  necessary  to  flow 
the  plate  once  more,  or,  in  fact,  many  times  more,  until  the 
surface  is  in  every  respect  irreproachable.  It  is  folly  to 
ignore  bad  workmanship  at  the  outset,  by  allowing  a  faulty 
plate  to  pass  ;  for  the  rest  of  the  labor  will  be  all  invain.  As 
soon  as  the  film  is  uniform,  the  plate  is  reared  on  the  dry- 
ing-rack to  dry.  Of  course  such  a  rack  must  be  located  in 
a  clean  place,  where  there  is  neither  dust  nor  draughts  of 
air.  This  sort  of  work  can  be  performed  during  idle  or 
unoccupied  hours. 


394 


THE  PORCELAIN  PICTURE. 


Some  of  the  dealers  in  photographic  stock  keep  porcelain 
plates  for  sale,  which  are  already  coated  with  albumen. 

Coating  the  Opal  Plates  with  Collodion. 

Any  of  the  bromo-iodized  collodions  in  commerce  will  be 
suitable  for  the  preparation  of  opal  pictures.  If  the  opera- 
tor wishes  to  make  his  own  collodion,  he  may  follow  the 
following  formula : 

Alcohol,  6  ounces. 

Ether,  5  ounces.  ,  ,  , 

Pyroxyline,   60  grains,  \  (™re  or  less'  f  ma? 

Iodide  of  cadmium,.    .    .    .    40  grains.  <     be  required.) 
Bromide  of  cadmium,     ...  20  grains. 
Iodide  of  ammonium,  ...     10  grains. 

Make  the  solution  of  the  cotton  and  salts  in  the  usual  way, 
and  set  it  aside  for  a  number  of  days  to  settle  and  ripen. 
It  is  then  filtered  or  decanted  from  the  sediment,  and  is 
ready  for  use. 

Each  plate  is  coated,  after  first  warming  it  and  then 
allowing  it  to  cool,  like  any  other  glass  plate ;  and,  when 
the  film  has  set,  the  plate  is  immersed  in  the  silver-bath,  and 
retained  there  until  the  soluble  iodides  and  bromides  have 
been  sufficiently  converted  into  iodide  and  bromide  of  silver. 
It  is  then  taken  out,  allowed  to  drain,  and  placed  in  the 
plate-holder,  which  is  immediately  transferred  to  its  posi- 
tion in  the  copying  camera.  At  the  anterior  end  of  the 
camera  the  negative  is  placed  in  its  holder ;  the  film  of  the 
negative  looks  toward  the  lens ;  and  the  picture  is  inverted, 
a  condition  which  aids  in  focusing. 

Negative  for  the  Porcelain  or  Opal  Picture. 

It  is  quite  an  art  to  take  a  good  and  proper  negative  for 
this  process,  as  well  as  for  the  solar  camera.  The  qualities 
of  the  two  negatives  are  exactly  the  same.  Such  a  negative 
must  be  clear,  sharp,  full  of  detail,  endowed  with  the  three 
gradations  of  shades,  lights,  and  middle  tones,  and  yet, 
after  all,  it  must  be  very  thin.  Now,  how  can  such  a  nega- 
tive be  taken  ?  Certainly  not  if  the  exposure  is  only  long 
enough  for  an  ambrotype,  because  then  the  middle  tones 
will  be  wanting.  You  must  expose  for  a  full  negative,  and 
develop  so  as  to  get  the  proper  result.  The  collodion, 
too,  is  made  one  half  more  dilute  with  a  mixture  of  equal 
volumes  of  ether  and  alcohol.  An  iron  developer,  suffi- 
ciently restrained  with  acetic  acid,  will  undoubtedly  be 


THE  PORCELAIN  PICTURE. 


395 


the  best;  for  the  collo-developers  in  general  produce  too 
much  intensity  in  the  shades,  whilst  the  lights  themselves 
are  scarcely  acted  upon.  Such  contrast  is  a  bad  condition 
in  the  negative  for  copying  purposes.  Of  course,  intensify- 
,  ing  is  out  of  the  question,  being  altogether  unnecessary,  if 
the  negative  is  only  complete  in  detail  and  gradation. 

Nor  is  it  necessary  to  varnish  negatives  for  this  process ; 
for  every  little  flaw  or  speck  in  the  varnish  is  transcribed 
by  the  rays  of  light  upon  the  porcelain  picture  in  copying. 

It  is  true,  porcelain  pictures  can  be  obtained  from  a  nega- 
tive intensified  for  printing  on  paper ;  but  the  results  with 
such  a  negative  are  far  from  being  pleasing  and  artistic, 
with  every  assistance  to  boot.  Such  assistance  consists  in 
cutting  out  a  shield  in  thin  paper,  that  shall  hide  or  cover 
up  the  thinnest  parts  of  the  negative  and  allow  time  for  the 
dense  parts  to  be  acted  upon.  If  this  precaution  were  not 
taken,  the  porcelain  picture  would  be  a  black  and  white 
imagine,  without  *  any  detail  and  intermediate  tones ;  it 
would  be  a  horrid  picture !  Such  as  is  but  too  frequently 
paraded  as  a  splendid  result !  But  make  your  negatives  as 
we  have  just  described  them,  and  you  will  see  the  difference 
of  results,  when  the  two  pictures  stand  side  by  side  in  stern 
contrast. 

Copying  cameras  can  be  obtained  from  the  stock-dealers, 
made  expressly  for  the  purpose  of  preparing  opal  pictures. 
They  are  constructed  neatly  and  with  accuracy.  Between 
the  lens  and  the  negative  there  is  a  movable  frame  carry- 
ing a  vignette,  which  can  be  shaped  according  to  the  re- 
quirements of  the  case,  and  introduced  and  adjusted  with 
facility. 

The  focusing  of  the  negative  on  the  ground  glass  is 
effected  roughly  with  the  naked  eye,  and  finally  with  the 
utmost  degree  of  refinement  by  means  of  a  magnifying  lens. 

In  the  winter  season  the  negative  may  be  directed  to  a 
bank  of  snow,  and  in  summer  to  a  white  cloud  ;  or  a  door, 
covered  with  a  white  reflecting  surface  and  moving  on  a 
hinge,  may  be  adjusted  in  front  of  the  negative  at  an  angle 
of  forty-five  degrees,  (more  or  less,)  in  order  to  receive  the 
light  from  the  sky  and  to  reflect  it  along  the  axis  of  the 
lenses.  Such  an  arrangement  is  very  practical  at  all  sea- 
sons of  the  year,  and  can  be  placed  beneath  the  skylight, 
without  entailing  any  necessity  of  opening  a  window. 


396 


THE  PORCELAIN  PICTURE. 


Exposure  of  the  Opal  Picture. 

The  exposure  can  not  be  determined  beforehand,  de- 
pending as  it  does  on  such  a  variety  of  conditions ;  as,  for 
instance,  on  the  focal  power  of  the  lens,  the  perfection  of 
the  lens,  the  state  of  the  weather,  the  season  of  the  year, 
the  time  of  the  day,  the  brightness  of  the  light,  the  sensi- 
tiveness of  the  chemicals  used,  etc.,  etc.  Begin  with  a 
short  exposure  first,  and  proceed  gradually  until  the  picture 
is  correct. 

Development  of  the  Picture. 

Greater  care  is  required  to  exclude  all  actinic  light  whilst 
developing  a  porcelain  picture,  than  in  the  development  of 
any  other  sort  of  collodion  picture  ;  probably  from  the  cir- 
cumstance that  every  trace  of  development  is  so  easily  dis- 
tinguished when  projected  on  the  white  porcelain  surface 
beneath.  In  reality,  probably,  the  same  amount  of  care  and 
precaution  is  necessary  with  every  negative ;  but  the  errors 
and  troubles  are  not  so  visible  in  these  as  in  that. 

The  developer,  too,  has  to  be  diminished  in  strength,  and 
must  be  quite  clear  and  free  from  extraneous  organic  mat- 
ter. 

Formula  for  the  Developer. 

Protosulphate  of  iron,   2  drachms. 

Water,   8  ounces. 

Acetic  acid,   6  drachms. 

Alcohol,   3  drachms. 

Pour  a  sufficient  quantity  of  this  developer  over  the  plate 
and  watch  the  progress  of  the  development.  If  the  exposure 
has  been  right,  the  picture  will  soon  appear  and  become 
sufficiently  intense.  Arrest  the  development  in  time,  that 
is,  as  soon  as  the  image  is  complete  in  detail,  although  not 
very  intense,  by  plunging  the  plate  into  a  dish  of  water. 
Wash  the  plate  w^ell  and  then  fix  the  picture  in  a  saturated 
solution  of  hyposulphite  of  soda.  We  prefer  using  a  fresh 
portion  of  the  hyposulphite  for  each  plate,  for  we  have  al- 
most invariably  observed  that  an  old  hyposulphite  bath 
produces  gray  or  dark-colored  stains  in  the  collodion  film, 
in  places  where  there  were  none  before.  The  picture,  being 
thus  cleaned  and  fixed,  is  thoroughly  washed,  and  may  then 
be  examined  by  diffused  light. 

Clarifying  the  Porcelain  Picture. 

With  the  best  and  most  successful  manipulations,  it  fre- 
quently happens  that  there  are  stains  on  the  corners  of  the 


THE  PORCELAIN  PICTURE. 


397 


plate,  and  on  other  parts,  and  the  white  of  the  collodion 
film  is  not  sufficiently  white.  The  stains  are  removed  ex- 
peditiously in  the  following  manner  : 

Prepare  in  the  first  place  tincture  of  iodine  by  dissolving 
twenty  grains  of  iodine  in  an  ounce  of  alcohol.  Have  on 
hand  a  vial  of  a  solution  of  cyanide  of  potassium,  such  as  is 
used  for  fixing  purposes  ;  and  place  a  large  dish  of  water 
right  in  front  of  you.  A  beaker  glass  full  of  water  also  is 
placed  in  a  convenient  place  where  it  can  be  used  with 
facility. 

Now  proceed  to  work  ;  drop  a  little  of  the  tincture  on  a 
given  stain,  and  see  that  it  does  not  come  near  any  of  the 
delineations  of  the  picture  as  it  spreads.  If  there  is  any 
danger  of  this  result,  immerse  the  plate  immediately  in  the 
water  beneath.  The  iodine  combines  with  the  silver  stain 
and  converts  it  into  iodide  of  silver,  which  immediately  dis- 
appears as  soon  as  the  cyanide  solution  is  applied.  If  some 
portion  of  the  stain  still  remains,  apply  more  tincture  of 
iodine,  wash  the  spot,  and  dissolve  it  with  the  cyanide.  In 
this  way  all  stains  may  be  removed,  unless  some  of  them 
should  be  located  on  or  near  the  picture  itself ;  in  this  case 
the  tincture  would  spread  and  convert  the  delineations  of 
the  picture  into  iodide  of  silver,  which  would  be  .removed  as 
soon  as  the  cyanide  is  applied.  It  is  better  to  reject  such 
an  unfortunate  picture  at  once,  rather  than  lose  your  time 
in  attempts  at  correction. 

If  the  white  of  the  collodion  is  not  stained,  but  of  a  slight 
gray  tinge,  a  considerable  improvement  is  effected  by  flow- 
ing the  plate  with  dilute  nitric  acid,  which  dissolves  the 
gray  metallic  tinge,  and  renders  the  collodion  white. 

All  stains  being  thus  removed,  and  the  collodion  film 
rendered  clear  and  white,  the  next  operation  consists  in 
toning  the  picture. 

If  the  picture  is  intended  to  be  stippled,  or  indeed  only 
colored,  very  little  toning  is  necessary.  To  tone  the  porce- 
lain picture  completely,  when  it  is  to  remain  uncolored,  is  a 
compound  operation. 


The  plate,  being  still  wet,  is  covered  quickly  with  the  above 
solution.  The  tone  of  the  picture  soon  changes  to  a  blue- 
black,  and  then  a  retrograde  action  seems  to  start  up.  Wash 
off  the  toning  solution  immediately  when  this  action  com- 


Toning  Solution. 


0 


Terchloride  of  gold, 
Water,  .... 


1  grain. 

2  ounces. 


398 


THE  PORCELAIN  PICTURE. 


mences.  It  frequently  happens  that  this  operation  is  all 
that  is  needed ;  and  then  again,  there  are  cases  where  the 
following  additional  toning  solutions  are  found  to  give  a 
richness  not  to  be  attained  by  the  gold  solution.  Make  the 
following  solutions : 

m.  1. 


Bichloride  of  mercury,   1  drachm. 

Water,   1  ounce. 

No.  2. 

Citric  acid,   1  drachm. 

Water,   2  ounces. 

Intensifying  Solution. 

Of  No.  1,   1  drachm. 

Of  No.  2,   1  drachm. 

Water,   10  drachms. 


Cover  the  plate  with  a  sufficient  quantity  of  the  intensify- 
ing solution,  which  works  with  great  rapidity,  and  -converts 
the  tone  into  an  agreeable  black.  Watch  proceedings  care- 
fully, and,  as  soon  as  the  tone  is  pleasing,  wash  off  the 
solution  immediately.  The  picture  now  will  be  complete. 
The  plate  is  finally  thoroughly  washed  under  the  tap,  and 
then  dried.  It  will  be  unnecessary  to  varnish  the  film,  if 
the  plate  is  to  be  mounted  in  a  case  with  a  glass  in  front, 
particularly,  too,  if  the  preservative  glass  is  convex. 

To  Prepare  Opal  Pictures  by  Contact  Printing. 

There  are  two  independent  methods  of  printing  by  con- 
tact, the  one  by  the  direct  rays  of  the  sun,  the  other  partly 
by  light  and  partly  by  development.  We  shall  explain  an 
example  of  either  of  these  two  methods. 

In  both  these  processes  it  is  quite  indispensable  that  the 
porcelain  glass  shall  be  flat  and  smooth,  otherwise  it  will 
not  be  easy  to  bring  the  negative  and  the  porcelain  plate 
into  intimate  contact.  It  is  equally  requisite,  too,  for  the 
negative  to  be  endowed  with  the  same  conditions  of  flat- 
ness and  smoothness. 

The  negatives,  therefore,  for  contact  printing  must  be 
taken  on  flattened  plate-glass ;  and  the  porcelain  plates  you 
must  select  yourself,  and  afterward  grind  them  flat.  This 
is  rather  a  tedious  operation  ;  but  if  you  have  a  boy  in  your 
establishment  he  can  easily  be  set  to  work  and  perform  this 
task.  Many  of  our  stock  dealers  grind  porcelain  plates,  and 
keep  them  on  hand  ready  for  the  operation. 


THE  PORCELAIN  PICTURE. 


399 


To  Grind  Porcelain  Plates  Flat  for  Contact  Printing, 

Upon  the  upper  surface  of  a  flat  table  fix  with  glue,  or, 
still  better,  with  small  screws  or  tacks,  slips  of  hard  wood, 
somewhat  thinner  than  the  thinnest  of  the  porcelain  plates 
to  be  ground,  in  the  form  of  a  rectangular  frame  just  large 
enough  for  a  given  sized  plate  to  lie  compactly  within  it 
and  not  stir  when  submitted  to  friction.  A  flat  porcelain 
plate  is  placed  in  this  frame,  and,  when  in  position,  it  is 
evident  its  upper  surface  will  be  higher  than  the  surface  of 
the  slips  of  wood  around  it. 

Secondly,  a  small  rectangular  piece  of  wood  is  selected 
of  the  shape  and  thickness  of  an  ordinary  book,  and  about 
an  inch  longer  and  wider  than  the  plate  to  be  ground.  A 
similar  rectangular  frame  is  constructed  and  screwed  upon 
one  of  the  flat  sides  of  this  piece  of  wood,  to  accommodate 
another  plate  when  placed  within  it.  The  plate  must  be 
quite  tight  when  it  lies  within  the  frame,  so  as  not  to  fall 
out  when  the  wood  is  turned  wrongside  up. 

Scatter  some  fine  emery  powder  upon  the  porcelain  plate 
lying  on  the  table  and  moisten  it  with  water  ;  now  lay  the 
other  plate  upon  the  emery,  and  by  means  of  the  wooden 
handle,  as  it  were,  in  which  it  is  located,  rub  the  two  plates 
together,  backward,  forward,  round  about,  and  in  all  di- 
rections, adding,  as  occasion  may  require,  both  more  emery 
and  more  water,  until  the  surfaces  of  the  two  plates  are  not 
only  ground,  but  lie  evenly  and  horizontally  and  in  perfect 
contact  with  one  another.  The  precautions  necessary  to  be 
taken,  are,  to  be  quite  certain  that  there  are  no  particles  of 
sand  or  emery  in  the  powder  larger  than  those  obtained  by 
subsidence  ;  for  a  single  particle  will  scratch  the  surfaces  so 
deeply  that  it  becomes  almost  impossible  afterward  to  grind 
the  plates  sufficiently  deep  to  eradicate  them. 

As  soon  as  the  two  surfaces  lie  in  intimate  contact,  they 
are  thoroughly  washed  and  afterward  ground  with  finer 
emery  dust.  The  plates  at  last  are  taken  out  of  the  rectan- 
gular frame,  carefully  washed,  dried,  and  packed  away  for 
use. 

To  pHnt  on  Ground  Opal  Glass  by  Contact  by  means  of 
the  Collodio-chloride  Process. 

Coat  the  plates  previously  with  dilute  albumen,  as  before 
described ;  and,  as  soon  as  the  plates  are  dry,  they  are  ready 
to  receive  the  sensitized  collodio-chloride.  This  collodion  is 
prepared  as  follows  • 


400 


THE  COLLODIO-CHLOKIDE  PROCESS. 


Formula  for  the  Collodio-chloride. 

We  are  indebted  to  G.  Wharton  Simpson,  M.A.,  for  the 
discovery  of  this  process  ;  and  the  following  formula  by 
Mr.  Britton  is  a  neat  way  of  preparing  the  collodion.  Pre- 
pare  the  four  following  stock  solutions  : 

No.  1.  Plain  Collodion. 

Alcohol,  10  ounces. 

Ether,   10  ounces.  ,  ,  , 

 120    i  ^utir may 

Shake  the  mixture  well  until  the  cotton  is  dissolved,  set  it 
aside  for  a  few  days  ;  decant  and  filter  when  required  for 
use. 

No.  2.  Nitrate  of  Siher  Solution. 

.Nitrate  of  silver,  2  drachms. 

Distilled  water,  2  drachms. 

No.  3.  Chloride  of  Calcium  Solution. 

Chloride  of  calcium,  32  grains. 

Alcohol,   2  ounces. 

No.  4.  Citric  Acid  Solution. 

Citric  acid,  32  grains. 

Alcohol,   2  ounces. 

To  one  ounce  of  plain  collodion  the  preceding  solutions 
are  added  in  the  following  proportion  : 

To  a  drachm  of  alcohol  add  nine  minims  of  No.  2,  and 
add  this  to  the  collodion,  which  must  be  well  shaken.  Now 
add  a  drachm  each  of  No.  3  and  No.  4  to  the  collodion ; 
shake  the  mixture  intimately ;  it  is  now  ready  for  use.  Some 
operators  add  two  drops  of  castor  oil,  or  three  or  four  of 
sweet  oil  to  each  ounce  of  the  collodio-chloride,  in  order  to 
prevent  bronzing  during  the  printing  operation.  The  col- 
lodio-chloride, being  a  highly  sensitive  substance  to  light, 
must  be  kept  in  a  non-actinic  bottle  and  in  a  dark  room. 

Coating  the  Porcelain  Plate  with  the  Collodio-chloride. 

The  albumenized  plate  is  first  warmed  over  a  flame  or 
stove,  and  when  cold,  the  collodio-chloride  is  poured  over 
it  in  the  same  manner  as  ordinary  collodion.  This  opera- 
tion, naturally,  is  performed  in  the  dark-room.  The  film  is 
allowed  to  dry,  by  placing  the  plate  on  a  drying-rack  in  a 
dark  corner  of  the  room.  As  soon  as  the  film  is  thoroughly 


THE  COLLODIO-CHLORIDE  PROCESS. 


401 


dry,  the  plate  is  transferred  to  the  fuming-cupboard,  where 
it  is  allowed  to  remain  in  the  fumes  of  ammonia  for  about 
three  minutes.  From  these  fumes  it  is  placed  again  on  the 
drying-rack  for  five  minutes,  and  afterward  placed  upon 
the  negative  in  the  opal  plate-holder. 

The  plate-holders  for  opal  pictures  are  of  a  peculiar  con- 
struction. The  operator  is  aware  that  the  ordinary  print- 
ing frame  could  not  be  used,  from  the  fact  that  the  porce- 
lain plate  can  not  be  bent  back  and  examined  like  a  piece 
of  albumen  paper.  All  the  frames  for  this  purpose  are  so 
arranged  that  one  part  holds  the  negative,  and  the  other 
the  opal  plate,  each  of  these  parts  working  on^  hinges, 
and  allowing  the  picture  to  be  examined  and  replaced  with- 
out having  disturbed  the  relative  position  of  the  opal  plate 
and  negative.  The  first  printing-frame  for  this  purpose  was 
invented  by  Mr.  Shive,  of  Philadelphia ;  in  its  present  im- 
proved form  it  answers  every  variety  of  application.  An- 
other frame,  which  is  exceedingly  neat  and  practical,  is  made 
and  sold  by  Mr.  Chapman,  of  ISTew-York.  A  third,  equally 
ingenious  as  the  preceding,  and  as  practical  probably,  is 
made  and  sold  by  the  firm  of  H.  &  E.  Anthony,  New- 
York.  It  is  possible  there  are  other  forms,  but  we  are  ac- 
quainted with  these  alone. 

The  sensitized  plate  is  exposed  to  the  sun  or  diffused 
light,  and  printed  in  the  same  manner  as  a  sensitized  sheet 
of  albumen ;  in  fact,  the  film  contains  the  same  salt  in  either 
case,  namely,  the  chloride  of  silver.  It  is  necessary  to  print 
a  little  deeper  than  is  required  in  the  finished  picture ;  be- 
cause its  intensity  is  slightly  diminished  by  the  subsequent 
operations  of  toning  and  fixing. 

Toning  and  Fixing  of  the  Collodio-chloride  Print. 

The  plate  is  removed  from  the  printing-frame,  and  wash- 
ed gently  in  order  to  remove  the  soluble  salts  of  silver,  etc. ; 
it  is  then  immersed  in  a  weak  gold  toning  solution,  and 
toned  precisely  the  same  as  a  print  on  paper.  When  the 
depth  of  tone  is  suitable,  the  plate  is  taken  out  of  the  gold 
bath,  thoroughly  washed  and  then  placed  in  the  fixing 
solution:  two  ounces  of  hyposulphite  of  soda  in  twenty 
ounces  of  water.  As  soon  as  all  the  unaltered  silver  salt 
has  been  removed,  the  plate  is  finally  thoroughly  washed 
either  by  soaking  some  time  in  several  changes  of  water, 
or  under  the  tap. 

A  richer  black  may  be  communicated  to  the  picture  by 
treating  it  at  this  stage  with  the  solution  of  bichloride  of 


402 


OPAL  PICTURE  BY  CONTACT. 


mercury  and  citric  acid,  recommended  as  the  final  toning 
solution  of  the  opal  picture  by  the  wet  process. 

This  print,  after  it  has  been  carefully  washed,  is  dried, 
and  may  be  colored  and  varnished,  or  not,  according  to 
taste  and  circumstances. 

To  take  an  Opal  Picture  by  Contact  on  a  Bromo-iodized 

Film. 

Any  of  the  dry  processes  would  be  suitable  for  this  pur- 
pose ;  but  we  give  preference  to  the  dry-tannin  process, 
probably-owing  to  the  fact  that  we  are  most  conversant 
with  it. 

Coai  the  cleaned  plates  with  albumen,  as  before  recom- 
mended, and  when  dry,  flow  them  with  any  good  bromo- 
iodized  collodion  made  by  our  stock-dealers.  Let  the  film 
set,  then  immerse  it  in  the  silver-bath.  In  fine,  wash  and 
sensitize  the  film  in  the  manner  minutely  explained  in  the 
chapter  "  A  Reliable  Tannin  Process." 

The  dry  porcelain  plate  is  then  placed  in  contact  upon 
the  negative  in  the  ordinary  printing-frame,  which  lies  on  a 
piece  of  smooth  board  a  little  longer  than  itself.  The  slide 
is  removed  as  it  thus  lies  on  the  board.  In  this  way  it  is 
carried  on  the  board  into  the  light  either  directly  beneath 
the  skylight  or  in  an  open  doorway  or  window.  The  board 
is  held  in  the  left  hand;  the  right  hand  now  seizes  the 
printing-frame  and  turns  it  over  and  thus  exposes  the  nega- 
tive to  the  light  for  one  or  more  seconds,  as  may  be  found 
necessary.  A  single  second  is  frequently  a  sufficient  ex- 
posure. The  frame  is  again  laid  flat  upon  the  board,  so 
that  the  negative  is  again  excluded  from  the  light,  and  is 
then  carried  into  the  dark-room  for  development.  All  the 
subsequent  operations  are  in  every  respect  the  same  as  those 
already  described  for  the  development,  etc.,  of  a  tannin 
negative. 

If  the  plate  is  in  any  way  stained,  it  may  be  treated  as 
described  in  the  article  on  the  preparation  of  opal  pictures 
by  the  wet  process. 

In  both  these  processes  for  printing  by  contact,  the 
vignette  arrangement  is  attached  to  the  printing-frame  in 
front  of  the  negative  in  the  usual  manner. 

This  print  may  receive  a  system  of  toning  exactly  similar, 
from  beginning  to  end,  to  the  one  used  and  recommended 
for  toning  porcelain  pictures  by  the  wet  process,  if  found 
necessary. 


THE  EBURNEUM  PROCESS. 


403 


If  a  porcelain  print  is  to  be  handed  over  to  the  artist  to 
be  colored  by  stippling,  he  will  prefer  receiving  the  picture 
full  of  detail,  of  course,  but  not  intense  and  scarcely  at  all 
toned;  for  all  that  he  requires  is  a  complete  likeness,  but 
faint,  in  order  that  he  may  give  the  requisite  brilliancy  of 
light  and  shade  by  the  correct  intermixture  of  color. 

On  the  contrary,  the  toning  and  proper  intensity  must  be 
present,  if  the  coloring  is  to  be  effected  either  by  dry  colors 
or  a  thin  wash  of  wet  colors,  for  in  these  two  cases  the 
shades  are  already  effected,  and  the  lights  alone  require 
color. 


The  prints  made  by  this  process  have  a  striking  resem- 
blance to  those  on  ivory,  hence  the  name  from  the  Latin 
word  Ebur,  (ivory.)  They  are  exceedingly  soft  and  bril- 
liant, and  never  fail  to  give  great  satisfaction.  They  are 
altogether  superior  to  the  Sennotype  or  Typolite,  which 
will  be  described  hereafter,  from  the  fact  that  they  do  not 
change  by  keeping.  This  process  originated  with  Mr. 
Burgess,  of  Norwich. 

The  first  part  of  the  process  consists  in  obtaining  a  trans- 
parent positive  on  glass,  which  can  easily  be  separated 
from  the  glass  plate  afterward  and  transferred  to  another 
medium.  Mr.  Wenderoth,  of  Philadelphia,  was  the  first 
to  describe  a  method  of  preparing  glass  plates  by  means 
of  which  collodion  films,  when  the  picture  is  finished,  can 
easily  be  separated  from  the  plate. 


The  wax  soon  dissolves  by  shaking,  and  then  the  solution 
is  ready  for  use.  The  plates  are  first  cleaned  thoroughly, 
and  then  coated  with  the  ethereal  solution  of  wax.  As 
soon  as  the  wax  film  has  concreted,  it  is  rubbed  off  with  a 
piece  of  clean  buckskin,  so  that  apparently  scarcely  any 
thing  is  left;  but  there  is  in  reality,  however,  sufficient 
wax  remaining  to  perform  the  office  required. 

The  collodion,  which  is  suitable  for  the  purpose,  must  be 
of  the  tenacious  kind,  one  that  is  not  rotten  or  easily  dis- 
integrated. The  following  formula  yields  a  collodion  of 
the  kind  intended : 


Wax  Solution  for  Coating  Plates. 


White  wax, 
Ether,  . 


2  grains. 
.  1  ounce. 


19 


404 


THE  EBURNEUM  PROCESS. 


Collodion  for  the  Eburneum  Process. 

Alcohol,   3  ounces. 

Ether,  4     "        t  ,  . 

Pyroxyline,  42  grains,    \  (mor£or  les?'  a*  faJ 

Iodide  of  cadmium,  28     «        <  re<lu^-) 

Iodide  of  ammonium,  ....  7  " 
Bromide  of  cadmium,   ....  14  " 

Mix,  dissolve,  and  set  aside  for  a  few  days  ;  then  decant 
and  filter  for  use. 

The  prepared  plates  are  coated  with  this  collodion,  and 
treated  either  with  the  wet  or  dry  process,  according  as  the 
transparency  is  to  be  taken  by  either  one  or  the  other  of 
these  pr^gesses.  $ 

We  will  suppose  the  positive  is  to  be  prepared  in  the 
copying  camera  by  means  of  the  wet  process.  It  will  not 
be  necessary  for  us  to  describe  the  method  of  taking  a 
transparent  positive ;  the  reader  is  supposed  to  be  acquaint- 
ed with  all  the  minutiae  ;  but  for  the  eburneum  process, 
since  the  collodion  film  is  to  be  mounted  on  the  ivory  back- 
ground wrong  side  up,  it  is  necessary  to  give  the  instruction 
by  which  such  a  transparent  positive  can  be  taken.  This 
is  briefly  done  by  simply  directing  the  negative  to  be  placed 
in  its  shield  with  the  film  looking  outward,  or  from  the  lens. 
By  this  arrangement  the  transparent  picture  will  be  laterally 
inverted,  and  when  the  white  gelatinous  film  is  poured  upon 
the  collodion  film,  becomes  indurated  and  separated  from 
the  glass,  the  picture  then  will  be  seen  through  the  collo- 
dion in  its  true  position. 

A  word  about  the  development  may  be  useful.  Since  the 
background  is  a  rich  ivory  or  porcelain  white,  the  minutest 
delineations  are  distinctly  seen  by  contrast ;  on  this  account 
the  development:  is  not  carried  to  the  same  extent  as  in  a 
negative.  The  same  depth  of  intensity  which  will  produce 
a  good  opal  picture  will  produce  a  good  transparent  posi- 
tive for  the  Eburneum  process.  The  developer  therefore 
must  be  weaker,  than  for  a  negative.  The  following  answers 
the  purpose  well : 

Protosulphate  of  iron,  1  drachm. 

Rain-water,  4  ounces. 

Acetic  acid,   3  drachms. 

Alcohol,   .      1  drachm. 

Gelatine,  1  grain. 

Stop  the  development  as  soon  as  detail  is  all  out,  and  be- 
fore the  shades  become  too  intense  ;  in  fine,  preserve  the 
picture  sharp,  bright,  full  of  detail,  but  still  somewhat 


THE  EBTTRNEUM  BACKGROUND. 


405 


faint.  Wash  and  fix.  The  transparent  positive  may  be 
toned  precisely  as  we  tone  a  porcelain  picture,  first  with  a 
good  solution,  and  afterward  with  the  acid  bichloride  of 
mercury,  that  is,  if  any  toning  is  found  necessary. 

If  during  the  development,  washing,  or  fixing,  the  film 
shows  any  tendency  to  peel  off,  the  author  recommends 
that  the  edges  be  varnished  to  the  depth  of  one  eighth  of 
an  inch  all  round  with  an  India-rubber  varnish,  .containing 
six  grains  of  India-rubber  dissolved  in  one  ounce  of  ben- 
zole. 

The  positive  is  now  washed  and  fixed,  and  again  thor- 
oughly washed ;  it  is  then  dried  either  Spontaneously  or  on 
the  drying-rack,  when  it  is  ready  for  the  second  operation. 

An  ordinary  negative  is  not  suitable  for  printing  by  con- 
tact, because  the  transparent  positive  would  be  laterally  in- 
verted when  mounted  on  the  opalescent  background. 

There  are  two  methods  of  obtaining  a  proper  negative 
for  this  purpose  ;  the  one  is  to  place  the  ground  surface  of 
the  focusing  lens,  as  well  as  the  collodion  film,  looking 
away  from  the  lens.  This  can  easily  be  effected  with  a 
plate-holder  made  expressly  for  this  purpose,  and  such  as 
we  have  already  recommended  in  Humphrey's  Journal. 

The  second  method  is,  first  to  take  a  transparent  positive 
by  means  of  the  camera,  as  already  described,  and  then  ta 
copy  this  positive  back  again  into  a  negative,  taking  care 
to  place  the  collodion  film  toward  the  lens  in  the  copying 
camera. 

The  next  operation  consists  in  the  preparation  of  the 
ivory  background,  and  the  fixing  of  the  collodion  picture 
upon  the  background. 

Eburneum  Background^ 

Place  an  ounce  of  fine  gelatine  in  five  ounces  of  water  to 
soak  for  a  number  of  hours  in  a  porcelain  evaporating  dish 
or  a  large  tea-cup.  At  the  expiration  of  this  time,  float 
the  dish  or  cup  in  a  pan  of  hot  water ;  by  this  means  the 
gelatine  will  soon  dissolve.  The  solution  is  afterward 
filtered  through  a  piece  of  sponge  or  a  plug  of  cotton-wool, 
placed  in  the  neck  of  a  tin  filter  so  arranged  as  to  allow 
hot  water  to  be  continually  in  contact  with  the  outside. 
Such  filters  are  very  useful  and  easily  constructed  by  any 
tinman.  The  fluid,  being  always  kept  hot,  filters  almost 
as  easily  as  water. 

Now  grind  together  in  a  mortar  the  following  mixture : 


406 


THE  EBURNEUM  BACKGROUND. 


Oxide  of  zinc, 
Glycerine, 
Water,  .  . 


1  ounce. 
1  " 
1  " 


Grind  them  into  a  very  fine  emulsion,  and  then  add  from 
time  to  time,  grinding  between  each  addition,  a  portion  of 
the  hot  filtered  gelatine,  until  the  mixture  is  of  the  proper 
consistence  for  flowing  over  a  plate  like  collodion,  and  is 
perfectly  white.  It  may  now  be  used  immediately,  and  the 
residue  is  put  away  for  future  use. 

The  transparent  positive  is  first  warmed  over  a  stove  or 
flame  and  then  placed  on  a  leveling-stand.  A.  sufficient 
quantity  of*  the  opal  gelatine  is  now  poured  upon  the  film 
containing  the  picture  so  as  to  completely  cover  it,  still 
pouring  on  more  as  long  as  it  shows  no  tendency  to  run 
over  the  edge  of  the  plate.  This  operation  is  to  be  per- 
formed in  a  warm  room  free  from  dust,  and  the  plate  is 
left  on  the  leveling-stand  to  dry  completely  and  gradually 
for  at  least  thirty-six  hours ;  there  will  be  no  harm  to  let  it 
remain  two  or  three  days  ;  but  to  attempt  to  remove  the 
compound  film  before  it  is  perfectly  dry,  which  requires 
in  general  about  the  number  of  hours  specified,  would, 
in  all  probability,  destroy  the  picture.  Supposing  the  film, 
however,  is  now  quite  dry,  it  is  coated  either  with  plain 
collodion,  ether  or  spirit  varnish,  which  soon  dries.  You 
may  now  proceed  round  the  edges,  cutting  an  incision 
through  the  films  clear  to  the  glass  with  the  point  of  a 
sharp  penknife,  when  it  will  be  found  that  the  compound 
film  can  be  easily  stripped  off  or  raised  up  from  the  glass 
plate  beneath.  The  edges  of  the  picture  are  next  trimmed ; 
and  now  the  picture  is  complete.  It  may  be  mounted  ac- 
cording to  taste. 

The  beauty  and  delicacy  of  the  eburneum-type  renders  it 
very  attractive,  and  the  preparation  is  by  no  means  diffi- 
cult when  the  operator  is  once  thoroughly  initiated  in  the 
minutiae. 

The  opal  gelatine  may  be  tinged,  during  its  preparation, 
with  a  little  color,  which  sometimes  increases  the  beauty^of 
the  picture. 

From  what  has  been  described  in  this  article,  it  is  a  very 
easy  thing  to  take  one  step  further,  and  apply  the  opal 
gelatine  films  to  thin  plates  of  iron,  such  as  are  used  for 
preparing  melainotypes.  Such  plates  will  eventually  be 
sold  by  the  gross. 

In  this  case,  however,  the  film  must  be  rendered  insoluble, 
which  is  effected  either  by  mixing  with  the  gelatine  solu- 


GLAZED  COLLODION  POSITIVES. 


407 


tion  a  proper  quantity  of  alum,  or  by  soaking  the  concrete 
and  dry  gelatine  film  in  a  solution  of  alum.  Upon  plates 
prepared  in  this  manner  opaltypes  may  be  taken  as  easily 
and  quickly  as  common  ambrotypes ;  it  is  true,  when  taken 
in  this  manner  they  will  not  be  so  brilliant  as  eburneum 
pictures,  because  the  gloss  of  the  collodion  is  wanting; 
but  the  gloss  or  glazing  can  be  communicated  to  the  sur- 
face by  coating  it  with  a  plain  collodion  film  transferred 
from  a  piece  of  highly  polished  plate  glass.  The  thin  plates 
of  iron,  which  contain  the  opal  gelatine,  are  sufficiently 
flexible  to  admit  of  this  operation.  The  two  surfaces  to  be 
cemented  together  are  first  moistened,  with  dilute  alcohol, 
which  causes  a  better  adhesion.  In  the  following  article 
the  reader  will  find  more  extended  instruction  on  this  sub- 
jert,  to  which  he  is  referred. 

How  to  Glaze  Collodion  Positives  and  Albumen 
Prints. 

This  operation  is  generally,  though  wrongly,  denomi- 
nated an  enamel  process.  Several  modes  have  been  pub- 
lished under  this  misnomer.  I  prefer,  therefore,  changing 
the  name,  and  reserving  the  word  enamel  to  represent  what 
it  means,  as  in  the  process  of  Joubert  and  others. 

Collodion  positives  are  glazed  in  the  following  manner  : 
If  the  film  to  be  glazed  is  a  picture  taken  on  an  opal  gela- 
tine film  on  a  thin  iron  plate,  or  when  the  opal  gelatine  film 
is  not  so  supported,  the  glazing  is  prepared  as  follows: 
Coat  a  piece  of  plate  glass  with  Wend  worth's  wax  solu- 
tion in  ether ;  when  this  film  is  concrete,  it  is  rubbed  off 
with  a  piece  of  clean  buckskin,  so  that  apparently  nothing 
remains  on  the  glass.  Over  this  comes  a  coating  of  a  tena- 
cious kind  of  plain  collodion,  which  is  perfectly  transpar- 
ent when  dry.  Next  dissolve  by  heat  one  drachm  of  clari- 
fied gelatine  in  an  ounce  and  a  half  of  water,  after  soaking 
some  time  in  the  water.  Filter  the  solution  while  hot 
through  a  piece  of  sponge.  Pour  a  sufftcient  quantity  of 
this  gelatine  solution,  still  warm,  over  the  collodion  film 
and  allow  it  to  dry  nearly. 

The  flexible  opal  gelatine  film  on  which  has  already  been 
taken  a  positive  by  reflected  light,  is  first  moistened  with 
dilute  alcohol,  (one  drachm  of  alcohol  to  four  drachms  of 
water,)  and  then  laid  on  the  gelatine  film,  which  is  still 
slightly  tacky,  but  it  must  be  laid  so,  by  bending  the  opal- 
gelatine,  that  all  bubbles  of  air  and  moisture  are  excluded. 


408 


GLAZED  PHOTOGRAPHS. 


By  looking  through  the  glass,  it  can  easily  be  seen  whether 
the  operation  has  been  successful ;  if  this  is  the  case,  the 
plate  glass  is  laid  flat  on  a  smooth  table  ;  several  folds  of 
blotting-paper  are  placed  on  the  back  of  the  opal-gelatine 
film  ;  on  these  is  placed  a  book  bound  in  calf;  and  Anally  a 
heavy  weight  on  the  top  of  this  keeps  the  parts  enumerated 
all  firmly  together.  In  this  condition  they  are  left  for  a 
number  of  hours,  in  fact  for  a  whole  day,  until  the  film  is 
thoroughly  dry,  and  the  cementation  is  complete.  When 
convenient,  now,  the  weight  is  removed,  and  you  may  pro- 
ceed to  cut  with  a  fine-pointed  penknife  round  the  edge  of 
the  opal-gelatine  film  to  the  glass,  then  by  raising  one  cor- 
ner with  the  knife,  it  will  be  found  that  the  appendage  of 
films  leaves  the  glass  plate  with  facility.  The  picture  now 
will  appear  as  if  covered  with  a  rich,  smooth,  and  polished 
film  of  glass ;  this  is  the  glazing  in  question,  the  enamel 
so-called. 

Let  us  suppose,  however,  that  the  picture  is  taken  on  an 
opal-gelatine  film  superimposed  on  a  rigid  background,  as, 
for  instance,  a  piece  of  glass.  The  proceeding  then  is 
slightly  changed.  A  piece  of  thin  mica  is  selected,  of 
which  one  surface  is  perfectly  smooth  and  free  from  frac- 
ture and  flaw  of  any  kind.  By  means  of  moisture  the 
other  surface  may  be  made  to  adhere  to  a  plate  of  glass. 
It  may  be  well  even  to  go  round  the  edges  with  a  strong 
solution  of  gum  so  as  thus  to  cement  the  mica  to  the  glass 
beneath.  When  dry,  coat  the  mica  with  the  ethereal  wax 
solution  as  before,  and  afterward  with  the  same  sort  of 
tenacious  or  tough  collodion  ;  when  the  latter  is  dry,  coat  it 
with  the  gelatine  solution  and  let  it  dry  nearly.  By  means 
of  a  penknife  the  film  of  mica  can  easily  be  separated  from 
the  glass  plate  beneath.  The  picture  on  the  opal-gelatine, 
having  been  first  treated  with  the  dilute  alcohol,  is  now 
ready  to  receive  the  glazing,  an  operation  which  is  per- 
formed precisely  as  before  described,  only  that  here  the  film 
of  glazing  on  the  mica  is  bent  and  brought  thus  into  con- 
tact with  the  positive.  The  rest  of  the  operation  is  the 
eame  exactly  as  already  described. 

To  Glaze  Photographs.    By  James  G.  Tunny. 

A  clean  plate  of  glass,  having  been  slightly  warmed,  is 
coated  with  white  wax  by  rubbing  a  small  piece  over  its 
surface  and  cleaning  off  with  a  clean  towel.  It  is  now 
coated  with  uniodized  collodion.    It  is  better  when  the 


GLAZED  PHOTOGRAPHS. 


409 


collodion  is  rather  tough  than  when  it  partakes  of  a  pow- 
dery quality.  An  ounce  of  gelatine,  having  been  soaked  for 
a  few  hours  in  twelve  ounces  of  water,  is  now  boiled  in  an 
earthenware  jar,  and  the  white  of  an  egg  is  added  to  clarify 
it.  The  solution,  while  warm,  is  filtered  through  a  piece  of 
flannel.  The  gelatine  is  now  ready  to  coat  the  collodion- 
ized  plate,  which  is  done  by  pouring  sufficient  on  the  centre 
of  the  plate  and  carrying  it  to  the  edges  by  a  slip  of  paper. 
After  moving  it  to  and  fro  for  a  few  seconds,  it  is  drained 
into  another  vessel,  so  that  it  may  be  used  again  ;  but  it 
must  not  be  returned  to  the  stock-jar,  as  it  may  carry  dust 
with  it.  Any  number  of  glasses  can  be  prepared  in  this 
way  ;  as  they  drain,  lay  them  on  a  bench  or  table.  After 
they  have  set  to  feel  a  little  "  tacky,"  take  your  prints 
which  have  been  thoroughly  washed,  lift  them  from  the 
tray  of  pure  water,  and  lay  them  immediately  on  the  pre- 
pared plate.  This  is  best  done  by  lifting  the  print  in  a 
horizontal  manner,  letting  its  edge  fall  on  the  edge  of  the 
glass,  and  by  a  gentle  motion  let  the  print  gradually  come 
into  contact  with  the  glass.  The  water  will  flow  before 
the  print,  which  entirely  prevents  the  formation  of  air- 
bubbles.  The  prints  can  also  be  put  down  dry,  but  the 
chances  of  air-bubbles  are  much  greater.  Eight  cartes  can 
be  laid  down  on  a  plate  twelve  by  ten.  I  find  it  best  just 
to  lift  the  cartes  from  the  water  and  lay  them  down  as  de- 
scribed. For  some  large  sizes,  I  have  found  it  very  easy 
first  to  lay  the  glass  on  a  leveling-stand,  then  to  cover  the 
gelatine  with  as  much  water  as  it  will  carry.  Lay  now  the 
print  thereon,  which  will  float ;  then  take  hold  of  the  two 
corners  of  the  glass,  pressing  the  print  into  contact  with 
the  gelatine  by  the  thumb,  and  lift  the  glass  gently  to  an 
angle.  The  water  running  off  will  leave  the  print  in  com- 
plete contact,  and  generally  without  an  air-bubble.  If 
there  should  be  any,  they  are  easily  seen  by  looking  at  the 
opposite  side,  when  by  means  of  a  gentle  pressure  of  the 
finger  any  such  can  be  led  to  the  side.  When  dry,  which 
generally  takes  about  eight  or  ten  hours,  they  can  be  sepa- 
rated by  passing  a  knife  round  the  edge  and  lifting  the 
whole.  Mount  in  the  ordinary  way.  I  prefer  having  the 
prints  trimmed  before  laying  them  down  on  the  glass,  as  I 
can  starch  the  backs  and  lay  the  board  on  before  removal 
from  the  glass,  thus  keeping  the  surface  much  more  perfect. 

For  locket  and  carte  portraits,  I  have  found  the  foregoing 
produce  exquisite  delicacy. 


410 


GLAZED  PHOTOGRAPHS. 


A  Second  Method  to  Glaze  the  Surface  of  Photographs. 

Coat  smooth  glass,  quarter  size,  if  for  a  card  picture, 
with  a  good  glutinous  uniodized  collodion.  The  collodion 
for  this  sort  of  work  may  be  prepared  as  follows : 

Alcohol,  ....  2  ounces. 
Ether,  3  ounces. 

Pyroxyline,     ...    30  grains,  (more  or  less,  as  required.) 

The  collodion  must  flow  evenly  over  the  plate  and  dry 
without  reticulations.  When  dry,  it  must  be  as  transparent 
and  colorless  as  the  glass  plate  beneath.  Hold  the  coated 
plate  over  the  stove  or  a  heated  plate  of  iron  until  it  is  dry, 
and,  while  still  warm,  pour  over  the  collodion  film  a  suffi- 
cient quantity  of  clear  negative  varnish,  prepared  with  al- 
cohol, so  as  to  cover  the  complete  surface,  in  the  same  man- 
ner as  a  negative  is  varnished.  After  draining,  place  the 
plate  on  a  leveling- stand.  The  card-picture  in  the  mean 
while  has  been  steeped  for  a  few  moments  in  dilute  alcohol ; 
it  is  now  taken  out  and  slightly  shaken,  to  drive  off  all  ex- 
cess of  the  dilute  liquid,  and  then  laid  upon  the  surface  of 
the  varnished  collodion  film,  beginning  at  one  end  and  gradu- 
ally proceeding  to  the  other,  and  thus  excluding  all  air-bub- 
bles that  might  otherwise  be  produced.  A  piece  of  soft  blot- 
ting-paper is  now  placed  upon  the  print,  and  by  means  of  a 
fine  paper-knife  the  print  is  pressed  carefully  into  uniform 
contact  with  every  part  of  the  varnished  collodion.  Final- 
ly, another  quarter-sized  plate  of  smooth  glass  is  laid  upon 
the  blotting-paper.  The  two  plates,  with  the  print  between 
them,  are  next  placed  upon  a  level  surface  and  submitted 
to  firm  pressure  by  means  of  a  heavy  weight.  In  this  con- 
dition the  plates  are  left  for  a  few  hours.  At  the  expiration 
of  this  time  the  weight  is  removed,  and  the  two  plates  are 
taken  up,  without  displacing  them,  and  the  collodion  plate 
is  held  over  the  stove  or  a  heated  plate  until  it  is  quite  dry. 
The  other  plate  is  then  removed,  the  blotting-paper  is  then 
first  dried  and  also  removed. 

The  final  operation  consists  in  removing  the  print  from 
the  glass  plate.  With  a  sharp-pointed  penknife,  guided 
by  the  edge  of  a  ruler,  cut  the  varnished  collodion  film 
along  the  edges  of  the  card-picture  to  the  glass  surface  be- 
neath, and  then  dip  the  plate  in  water  as  hot  as  the  hand 
can  bear  it.  By  thus  proceeding  with  its  glazed  coating  it 
will  peel  from  the  glass,  and  is  then  ready  for  mounting. 


GLAZED  PHOTOGRAPHS. 


411 


A  Third  Method.    By  F.  A.  Wenderoth. 

First,  rub  over  a  piece  of  clean  plate-glass  a  solution  of 
white  beeswax  in  ether;  the  excess  is  then  removed  and 
the  surface  is  rubbed  smooth,  so  that  apparently  nothing 
remains.  The  plate  is  next  coated  with  a  good  glutinous, 
transparent,  plain  collodion,  and  when  the  film  is  dry  it  is 
in  its  turn  coated  with  the  following  solution  of  gelatine : 

Gelatine,   2  ounces. 

Water,  16  ounces. 

Glycerine,  3£  drachms. 

Soak  the  gelatine  in  the  water  for  a  number  of  hours, 
then  apply  a  gentle  heat ;  the  gelatine  will  soon  dissolve. 
Then  add  the  glycerine. 

In  order  to  coat  the  collodionized  plate  with  this  solution 
of  gelatine,  it  is  first  placed  on  a  leveling-stand,  and  then 
as  much  of  the  solution  is  poured  upon  the  collodion  film  as 
will  remain  without  flowing  over  the  edges.  In  this  condi- 
tion it  is  left  in  a  clean,  dry  room  until  the  films  are  com- 
pletely dry. 

As  soon  as  the  gelatine  and  collodion  film  is  dry,  the 
print  to  be  glazed  is  immersed  for  half  an  hour  in  a  mixture 
of  equal  parts  of  alcohol  and  water.  Then,  just  before  bring- 
ing the  print  in  apposition  with  the  gelatine  film,  the  latter 
is  moistened  by  means  of  a  broad  camel's  hair  pencil  dipped 
in  the  same  dilute  alcohol  above  mentioned.  The  picture  is 
then  taken  and  laid  quickly  down  upon  the  gelatine,  begin- 
ning at  one  end  and  thus  driving  all  excess  of  the  dilute 
alcohol  and  air-bubbles  before  it.  A  piece  of  blotting-paper 
is  then  placed  upon  the  back  of  the  print,  and  by  means  of 
a  pallet-knife  the  print  is  pressed  into  intimate  contact 
with  the  gelatine  film  beneath.  As  soon  as  the  print  is  dry, 
an  incision  is  made  round  the  edges  of  the  print  and  through 
the  gelatine  and  collodion  films  to  the  glass  ;  by  means  of 
the  knife-point  the  picture  is  now  raised  from  the  glass  and 
is  ready  for  being  mounted.  If  the  operation  has  been  suc- 
cessful, the  surface  will  be  uniformly  glazed  ;  but  it  some- 
times happens  that  it  is  specked  with  a  number  of  unglazed 
points  and  spots.  By  pouring  a  sufficient  quantity  of  the 
gelatine  solution  upon  the  collodion  film,  so  as  to  complete- 
ly cover  it  and  to  incipient  running  over,  this  accident 
will  seldom  happen.  The  gelatine  solution,  of  course,  is 
poured  on  whilst  still  warm. 


412 


THE  MAGNESIUM  LIGHT. 


The  next  part  of  the  operation  is  to  mount  the  print. 
This  is  performed  in  the  following  manner : 

The  picture,  when  dried  and  trimmed,  is  laid  upon  the 
surface  of  a  clean  piece  of  plate-glass  placed  on  a  leveling- 
stand  ;  in  this  position  as  much  of  the  gelatine  solution 
above  mentioned,  but  diluted  one  half,  is  poured  upon  the 
back  of  the  print  as  it  will  hold  without  running  over. 
This  film  is  allowed  to  dry.  When  dry,  the  mount  is  im- 
mersed for  half  an  hour  in  the  dilute  alcohol,  and  the  gela- 
tine surface  having  been  moistened  with  the  dilute  alcohol 
by  means  of  a  broad  camel's  hair  pencil,  the  mount  is 
pressed  into  contact  with  the  gelatine  in  the  usual  manner, 
so  as  to  exclude  air-bubbles.  A  weight  is  placed  upon  the 
mount  for  an  hour  or  two.  The  print  after  this  time  will 
now  be  complete. 

How  to  Take  Photographs  by  the  Magnesium  Light. 

Several  of  the  metals  in  combustion  emit  an  intense  light 
either  in  the  form  of  incandescent  scintillations,  as,  for  in- 
stance, iron  and  steel,  or  of  a  dazzling  flame,  like  burning 
zinc  or  magnesium.  The  flame  in  the  two  latter  examples 
is  produced  by  reflection  from  the  cloud  of  vapor  raised 
from  the  metal  itself  in  the  form  of  oxide,  and  is  similar  to 
that  of  phosphorus  when  burning  in  a  jar  of  oxygen,  which, 
previous  to  the  formation  of  a  cloud  of  phosphoric  acid 
vapor,  occupies  a  small,  condensed,  incandescent  space  ;  but 
as  soon  as  sufficient  vapor  has  arisen,  this  becomes  illumin- 
ated intensely  and  emits  a  brilliant  white  light  all  round. 

Magnesium  is  the  only  metal  which  can  be  ignited  by  a 
common  match,  and  which,  when  so  ignited,  will  burn  in 
common  atmospheric  air.  Zinc  and  other  metals  may  be 
ignited  and  will  then  burn  in  oxygen  gas.  The  flame  from 
zinc  resembles  that  from  burning  magnesium,  and  has  about 
the  same  amount  of  actinic  action.  But  from  the  convenience 
of  being  enabled  to  obtain  one  of  the  most  brilliant  of  flames 
by  simple  ignition  in  atmospheric  air,  we  are  furnished,  in 
the  metal  magnesium,  with  another  important  photographic 
assistant ;  for,  by  means  of  this  metal,  we  are  enabled  to 
take  photographs  as  easily  by  night  as  by  day.  We  have 
succeeded  in  taking  both  portraits  and  stereographs  by 
night  by  means  of  this  wonderful  photographic  helpmate, 
and  the  specimens  of  these  operations,  as  they  lie  before  us, 
convince  us,  would  convince  the  most  exacting,  that  the 
process  is  in  every  sense  of  the  word  feasible. 


MAGNESIUM. 


413 


Magnesium. 

It  is  only  a  little  more  than  a  hundred  years  ago  that  the 
oxide  of  magnesium  was  distinguished  from  lime ;  up  to  this 
time  it  had  been  previously  confounded  with  it.  The  metal 
itself  is  never  found — like  gold,  silver,  and  copper — in  a  free 
or  uiicombined  state  in  nature,  so  that  it  was  only  after 
chemistry  had  emerged  as  a  science  that  it  became  reduced 
into  the  regular  condition  out  of  its  combinations.  The 
oxide  of  this  metal  is  found  combined  with  carbonic, 
silicic,  boracic,  sulphuric,  and  nitric  acids  ;  these  combina- 
tions occur  both  in  the  organic  and  inorganic  kingdom,  and 
from  this  fact  it  may  be  deduced  that  the  metal  is  an  abun- 
dant part  of  the  earth's  incrustation.  The  minerals  from 
which  the  various  preparations  of  magnesia  (oxide  of  mag- 
nesium) are  extracted  are  magnesite  and  hydromagnesite, 
both  carbonates  ;  these  are  found  in  Europe,  Asia,  and 
America.  Dolomite,  or  magnesian  limestone,  is  a  carbon- 
ate of  lime  and  magnesia,  and  is  frequently  used  as  a  build- 
ing material.  Marmolite  is  a  silicious  hydrate  of  magnesia. 
But  it  is  not  alone  from  these  minerals  that  magnesia  is  ex- 
clusively obtained  ;  it  is  found  in  combination  with  certain 
acids  in  the  mother  liquor  after  common  salt  has  crystallized 
out  of  sea- water  or  from  the  water  of  certain  inland  springs. 

Magnesia  and  the  carbonate  of  magnesia  have  been 
known  for  several  years  as  important  articles  in  the  Materia 
Medica,  but  it  is  only  a  short  time  since  the  metal  magnesi- 
um was  extracted  from  its  combinations,  or  even  known  to 
be  an  independent  and  separate  metal.  When  pure  and 
unalloyed,  magnesium  is  a  white  metal,  like  silver,  but 
much  lighter,  its  specific  gravity  being  only  1.75  ;  it  is  then 
not  quite  twice  as  heavy  as  water — in  fact,  it  will  swim  on 
concentrated  sulphuric  acid.  It  has  considerable  resem- 
blance to  the  metal  zinc  ;  it  has  nearly  the  same  color,  it 
burns  with  a  similar  flame,  produces  by  combustion  a 
capacious  flocculent  or  woolly  oxide,  and,  like  this  metal,  can 
be  distilled.  When  heated  in  oxygen  gas,  in  atmospheric 
air,  in  the  vapor  of  iodine,  of  chlorine,  and  of  sulphur,  it 
burns  with  great  brilliancy,  and  emits  when  burned  in  air  a 
bluish -white  flame,  which  is  perhaps  more  dazzling  than  any 
other  artificial  light ;  at  any  rate,  this  flame  is  endowed 
with  more  actinic  effect  than  that  produced  by  the  two 
charcoal  ions  in  the  galvanic  current,  by  the  oxyhydrogen 
light,  or  by  the  combustion  of  phosphorus  and  chlorate  of 
potassa. 


414 


MAGNESIUM. 


Magnesium  was  first  obtained  by  Sir  Humphry  Davy,  in 
1808,  by  passing  the  vapor  of  potassium  over  magnesia 
heated  to  a  white  heat.  Both  Bunsen  and  Matthiesen  have 
obtained  it  by  an  electrolytic  method.  Bunsen  and  Roscoe 
discovered  the  actinic  effect  of  its  flame — that  is,  the  great 
power  which  the  flame  possesses  in  decomposing  certain 
salts  of  silver,  etc. — during  their  investigations  in  the  spec- 
trum analysis  and  its  reversal,  and  it  was  by  them  pro- 
posed as  an  artificial  light  for  taking  photographs. 

The  Galvanic  Process  for  Obtaining  Magnesium. 

This  is  the  process  of  Matthiesen :  it  consists  in  fusing 
the  double  chloride  of  magnesium  and  potassium  in  a  cruci- 
ble, and  then  decomposing  the  fused  mass  by  means  of  an 
electric  current.  While  the  salts  are  thus  in  fusion,  the 
two  poles  of  a  powerful  galvanic  current  are  introduced,  the 
negative  pole  being  an  iron  wire  and  the  positive  a  piece  of 
coke.  Decomposition  commences  immediately  ;  the  metal 
magnesium  is  found  at  the  negative  pole,  while  chlorine 
affects  the  positive  pole,  the  coke  just  touching  the  fused 
mass.  This  process,  however  interesting  it  may  be,  has  not 
been  resorted  to  in  the  preparation  of  the  metal  magnesium 
for  commercial  purposes. 

The  Process  by  which  Magnesium  is  prepared  for  Commer- 
cial Purposes. 

This  is  a  modication  of  the  French  process  of  St.  Claire, 
Deville,  and  Caron,  and  one  practiced  by  Mr.  Sonstadt,  of 
Manchester,  England. 

The  chloride  is  the  salt  used  from  which  the  magnesium 
is  to  be  obtained.  But  this  salt  alone  can  not  be  dried  and 
fused  without  being  partially  decomposed  ;  on  this  account 
one  of  the  double  chlorides,  which  are  stable  salts  even 
whenTused,  is  used.  The  double  chloride  of  magnesium  and 
potassium  is  the  salt  selected  and  employed. 

This  double  salt  is  prepared  as  follows  : 

Dissolve,  in  a  given  volume  of  hydrochloric  acid,  carbon- 
ate of  magnesia  as  long  as  effervescence  is  produced,  or 
until  the  acidity  is  neutralized.  The  liquid  is  stirred  well 
after  each  addition  of  the  carbonate.  An  equal  volume  of 
the  same  acid  is  neutralized  with  carbonate  of  potassa. 
The  two  solutions  are  then  mixed  together  and  evaporated 
to  dryness.  The  dry  mass  is  then  fused  in  a  large  platinum 
crucible,  and  maintained  at  this  temperature  until  all  or- 


MAGNESIUM. 


415 


ganic  materials  are  destroyed.  The  fused  salt  is  now  poured 
out  upon  a  clean  iron  plate,  and  when  cold  it  is  broken  up 
into  pieces  and  and  preserved  in  closely-stoppered  bottles 
for  future  use. 

Reduction  of  the  Chloride  of  Magnesium. 

The  chloride  of  magnesium  is  reduced  to  the  metallic 
state  by  means  of  sodium  aided  by  heat.  One  part  of  sodi- 
um is  cut  up  into  small  pieces  and  placed  at  the  bottom  of 
an  iron  crucible  ;  it  is  then  covered  with  five  parts  of  the 
double  chloride  of  magnesium  and  potassium.  The  crucible 
is  then  closed  with  an  iron  lid  and  placed  in  a  furnace, 
where  it  is  gradually  raised  to  a  full  red  heat,  and  main- 
tained at  this  temperature  for  a  length  of  time  to  be  ascer- 
tained by  experience.  The  crucible  is  then  allowed  to  cool, 
and  the  cover  having  been  taken  off,  the  mass  is  extracted. 
The  salts  of  potassium  and  sodium  dissolve,  when  the  mass 
is  thrown  into  water,  and  at  the  bottom  of  the  vessel  are 
found  a  number  of  small  metallic  globules  of  magnesium. 
These  are  next  carefully  washed,  and  dried  as  rapidly  as 
possible  on  a  water-bath  ;  they  are  finally  placed  in  a  cruci- 
ble beneath  a  layer  of  the  double  chloride  of  magnesium  and 
potassium  and  fused  into  a  single  mass.  This  is  the  crude 
metal  magnesium. 

Purification  of  Magnesium  by  Distillation. 

Magnesium,  like  zinc  and  some  other  metals,  can  be  puri- 
rified  by  distillation  ;  but  since  this  metal  is  easily  oxidized, 
it  is  necessary  to  perform  the  distillation  in  an  atmosphere 
of  hydrogen.  An  iron  cylinder  or  crucible  is  first  nearly 
filled  with  the  crude  magnesium ;  by  a  certain  contrivance 
the  cylinder  or  crucible  is  then  emptied  of  its  oxygen  and 
filled  with  hydrogen.  This  crucible  is  connected  with  a 
receiver  which  in  like  manner  is  also  filled  with  hydrogen. 
The  connections  being  properly  made,  the  crucible  is"  now 
heated  to  a  white  heat,  when  the  metal  begins  to  rise  in 
vapor  and  condense  in  the  receiver.  The  operation  is  con- 
tinued until  the  whole  of  the  metal  has  been  distilled.  The 
concrete  mass  in  the  receiver  is  afterward  taken  out  and 
either  beaten  into  plates  or  drawn  into  ribbon  or  wire  in 
accordance  with  the  purpose  for  which  it  is  intended. 

How  to  Take  Photographs  by  the  Magnesium  Light. 

This  light  is  exceedingly  dazzling  and  has  to  be  managed 
bo  that  neither  the  lens  nor  the  eyes  of  the  sitter  receive 


416  PHOTOGRAPHS  BY  MAGNESIUM  LIGHT. 


the  direct  beam.  Hence  reflectors  have  to  be  used  ;  these 
may  be  cylindrical  or  spheroidal.  Those  which  are  sold  by 
the  Magnesium  Company  are  constructed  of  sheet  tin  in  a 
plain  semi-cylindrical  manner ;  the  upper  portion  is  pro- 
longed into  a  funnel-shaped  chimney  for  carrying  off  the 
heated  oxide  as  it  is  formed ;  the  lower  portion  terminates 
in  a  platform  for  receiving  the  ashes  as  they  fall.  Behind  is 
a  handle  by  which  the  operator  can  easily  direct  the  light  in 
any  given  direction.  Just  below  the  funnel-shaped  orifice 
above,  the  strands  of  magnesium  wire  or  ribbon  are  sus- 
pended, in  such  a  manner  that  the  lower  ends  terminate  a 
couple  of  inches  above  the  platform  below.  Three  or  more 
strands  can  thus  be  suspended  and  ignited  at  the  same  time 
by  twisting  the  terminal  ends  into  one  bundle. 

The  operator  stands  two  or  three  feet  on  one  side  of  the 
camera,  and  at  about  the  same  distance  from  the  sitter  as 
the  camera  stands  from  him.  On  the  opposite  side  of  the 
sitter  a  white  screen  is  fixed  and  in  such  a  manner  as  to  re- 
flect the  light  upon  the  opposite  side  of  the  sitter's  face. 
The  magnesium  light  is  elevated  above  the  head  of  the 
model  so  as  to  cause  his  shadow  to  fall  behind  upon  the 
floor  and  not  upon  the  background  behind,  which  otherwise 
would  exhibit  a  ghost  of  the  sitter.  This  difficulty  may  be 
obviated  by  another  method  :  an  assistant  is  placed  behind 
the  side  screen  and  furnished  with  a  single  strand  of  the 
magnesium  wire  ready  to  be  lighted  at  the  same  moment 
the  main  light  is  ignited.  This  secondary  light  is  intended 
to  illumine  the  background,  which  is  thus  very  effectually 
done  ;  but  it  is  quite  invisible  to  the  orifice  of  the  lens  as 
also  to  the  main  operator.  We  do  not  think  it  advisable 
to  move  the  principal  light  up  and  down  or  sidewise  during 
the  exposure,  as  some  have  recommended,  in  order  to  equal- 
ize the  lights  and  shades ;  this  object  must  be  effected  by 
the  proper  adjustment  of  reflecting  screens.  By  moving 
the  main  light  about,  the  reflection  on  the  eyes  changes  its 
place  and  thus  destroys  sharpness ;  such  an  act  would  be 
equivalent  to  opening  and  shutting  an  appendage  of  win- 
dows continually  upon  the  sitter  in  an  artist's  studio ;  the 
artist  would  become  utterly  bewildered  by  such  a  flood  of 
moving  light ;  and  his  draught  would  have  no  point  to  it. 

It  is  well  to  place  the  background  as  far  behind  the  sitter 
as  is  convenient.  Previous  to  igniting  the  ends  of  the  mag- 
nesium strands,  the  model  has  to  be  placed  in  focus.  Let 
an  assistant  stand  near  the  model,  after  the  latter  has  been 
properly  arranged  in  position,  with  a  lighted  lamp  held  so 


THE  DUPLEX  TYPE. 


417 


as  to  illumine  the  sitter's  eyes.  The  operator  then  will  have 
no  difficulty  in  getting  a  sharp  focus  on  the  ground  glass. 
The  lens  is  now  closed,  and  the  sensitized  plate  is  introduced. 

The  operator  next  takes  his  position  with  the  magnesium 
lamp  and  reflector  in  his  hand,  as  does  also  an  assistant  be- 
hind the  side  screen  with  the  secondary  light.  As  soon  as 
all  is  ready  the  two  lights  are  ignited  by  means  of  common 
lucifer  matches ;  the  lens  is  opened  and  the  slide  drawn ; 
the  exposure  commences.  If  the  strands  burn  right  with- 
out breaking,  and  do  not  go  out  midway,  by  the  time  that 
four  strands  have  thus  burned  out,  the  exposure  will  have 
been  sufficiently  long  under  favorable  circumstances.  Close 
the  slide,  and  proceed  at  once  to  the  development  of  the 
plate.    Further  instructions  on  this  point  are  unnecessary. 

We  frequently  find  it  advantageous  in  obscure  weather, 
or  when  taking  photographs  of  our  domestic  chambers,  to 
use  the  magnesium  light  in  connection  with  daylight.  The 
results  are  good. 

Duplex  Type,  or,  How  to  take  Two  Pictures  of  the 
same  Person  on  the  same  Plate. 

This  process  or  operation  scarcely  deserves  the  name  of 
type;  the  chemical  and  optical  parts  of  the  operation  are  the 
same  as  in  the  common  process  of  taking  a  negative. 

In  the  first  place  let  us  define  what  the  picture  is.  This 
we  can  do  by  giving  an  example  :  On  the  same  card-picture 
are  perceived  the  identical  and  same  person  in  two  different 
positions ;  as  for  instance,  in  one  position  he  is  playing  the 
piano,  whilst  in  the  other  position  he  stands  behind  and  on 
one  side  of  himself  and  is  apparently  listening  to  the  music, 
or  he  may  be  in  a  position  so  as  to  accompany  himself  on 
the  violin  ;  and,  notwithstanding  all  this,  there  is  no  line 
in  the  card  to  indicate  that  the  picture  has  been  taken 
twice  ;  but  the  fact  is,  it  is  a  picture  that  is  taken  by  posing 
and  exposing  twice  on  the  same  plate. 

The  duplex  operation  is  effected,  or  may  be  effected,  in 
several  different  ways ;  but  we  give  preference  to  the  fol- 
lowing method : 

Fasten  a  curtain  in  the  middle  of  the  background  and  let 
the  folds  be  easy  and  graceful.  This  is  not  absolutely  ne- 
cessary, but  it  answers  our  purpose  in  the  description.  Se- 
lect one  of  the  folds  as  the  middle  line  to  divide  tlie  card- 
picture  into  two  equal  portions.  In  front  of  this  place  the 
piano  in  an  appropriate  and  natural  position,  so  that  the 


418 


THE  DUPLEX  TYPE. 


stool  stands  in  the  middle  or  near  the  middle  of  the  right 
half  of  the  curtain  when  seen  from  the  lens  in  the  camera. 
Let  the  sitter  now  take  his  seat  in  front  of  the  piano  with 
his  hands  on  the  keys  in  the  position  of  playing.  The  ope- 
rator now  fixes  his  lens  and  camera  so  that  the  picture  to 
the  right,  or  on  the  right  side  of  the  middle  line  of  the  cur- 
tain, occupies  now  about  one  half  of  the  illuminated  circle 
on  the  ground  glass  ;  the  focus  is  accurately  adjusted.  A 
screen  of  black  velvet  is  placed  halfway  between  (or  still 
nearer)  the  lens  and  the  left  side  of  the  piano,  etc.,  to  ex- 
clude all  the  parts  of  the  picture  to  the  left  of  the  middle 
line.  As  soon  as  this  part  of  the  picture  has  been  accurately 
focused,  the  screen  is  moved  to  the  opposite  or  right  side 
in  order  to  hide  all  that  part  of  the  picture  which  has  just 
been  focused,  and  thus  to  allow  the  other  half  to  be  com- 
posed and  adjusted  to  focus.  The  sitter  now  leaves  his 
seat  without  disturbing  it,  and  with  sufficient  observation 
as  to  regain  it  and  still  be  in  focus.  He  now  takes  his 
violin  and  has  to  move  about  at  the  request  of  the  operator 
until  he  finds  a  position  where  he  is  in  focus  ;  for  the  lens 
must  not  be  disturbed,  otherwise  the  other  picture  will  be 
out  of  focus.  He  must  also  assume  a  natural,  easy,  and  ap- 
propriate posture  with  the  violin  as  if  in  the  act  of  accom- 
panying the  other  sitter  at  the  piano,  (this  other  sitter  being 
himself  all  the  while.)  When  this  half  of  the  picture  is 
focused,  the  lens  is  closed,  the  sensitive  plate  is  introduced, 
the  slide  drawn,  and  the  proper  amount  of  exposure  made. 
Close  the  lens  again;  move  the  screen  to  position  No.  1, 
let  the  model  place  himself  on  the  stool  and  adjust  his  hands 
on  the  keys  ;  see  that  he  regains  the  position  where  he  was 
before  in  focus ;  now  remove  the  cap  of  the  lens  and  again 
make  the  necessary  exposure. 

The  negative  is  developed  in  the  usual  manner;  and  if 
the  adjustments  have  been  correctly  made,  the  two  pictures 
will  appear  together  without  any  line  of  division  between 
them. 

Mr.  Shive,  of  Philadelphia,  has  constructed  a  very  inge- 
nious sliding  screen  which  is  attached  to  the  top  of  the 
camera  by  means  of  a  lever,  which  can  move  over  the  pro- 
per amount  of  circular  arc  in  order  to  shut  and  close  one 
half  of  the  picture  alternately.  This  mechanical  arrange- 
ment is  called  a  Duplicating  Deflector  ;  it  answers  the  pur- 
pose well. 


THE  HELLENOTYPE. 


419 


Hellenotype. 


This  process  has  had  so  many  names,  and  been  patented 
go  often  under  different  names,  that  one  is  led  to  believe  in 
some  weak  point  in  the  process  that  renders  such  tergiver- 
sation a  necessity.  It  has  been  patented  in  Great  Britain 
several  times ;  in  the  United  States  just  as  often ;  in  Aus- 
tralia it  is  a  process  also  protected  by  a  patent.  Hallotype, 
Sennotype,  Ivory  type,  Typolite,  etc.,  are  some  of  its  names, 

The  Hellenotype  is  a  handsome  picture ;  but,  from  our  ex- 
perience, it  is  a  picture  that  fades  in  the  course  of  time,  it 
loses  its  brilliancy,  its  cream-like  or  ivory -like  whiteness, 
and  becomes  of  a  dusky  yellow.  If  there  were  any  means 
of  preserving  the  original  color  permanently,  this  sort  of 
picture  would  meet  with  deserved  approbation. 

To  prepare  the  Hellenotype  two  finished  photographs 
from  the  same  negative  are  required,  one  of  these  is  printed 
lightly,  the  other  is  rather  over-printed,  or  at  any  rate  it 
must  be  a  very  vigorous  print,  the  former  on  the  contrary 
being  much  fainter.  The  lighter  print  is  to  be  made  trans- 
parent by  whatever  means  we  may  possess  ;  such  means  we 
do  possess,  but  the  misfortune  is,  that  after  a  few  months 
the  transparency  changes  to  dullness,  and  the  whiteness  of 
the  paper  either  becomes  tawny  or  speckled.  The  varnishes 
used  do  not  easily  penetrate  the  albuminous  film ;  on  this 
account  it  is  better  to  print  the  lighter  photograph  on  plain 
paper.  This  print  is  then  immersed  in  the  following  var- 
nish : 

Spirits  of  turpentine,  (colorless,)  7  drachms. 


Place  the  mixture  in  a  warm  room  until  the  mastic  and 
balsam  are  thoroughly  dissolved.  The  print  is  left  in  this 
varnish  until  the  latter  has  penetrated  through  every  fiber, 
and  it  becomes  almost  as  transparent  as  a  plate  of  glass. 
It  is  then  taken  out  and  hung  up  to  dry.  As  soon  as  the 
transparent  picture  is  dry,  the  parts  that  require  coloring 
receive  a  uniform  layer  of  the  appropriate  color  on  the  back 
of  the  print ;  no  shading  is  needed,  because  the  picture  is 
already  provided  with  all  the  gradations  of  light  and  shade 
that  are  necessary ;  nor  is  much  care  required  in  laying  on 
the  color;  still  it  is  better  not  to  allow  one  color  to  in- 
trench upon  another,  or  overstep  its  limits.  This  part  of 
the  operation  being  finished,  the  colored  print  is  laid  upon 


Mastic,  (selected,)  

Venice  turpentine,  (finest  quality,) 
Canada  balsam,  (colorless,)    .  . 


1  drachm. 
3  drachms 
1  drachm. 


420 


THE  IVORYTYPE. 


the  uncolored  and  vigorous  print  in  such  a  manner  that  the 
corresponding  parts  of  the  upper  picture  are  superimposed 
upon  those  of  the  lower.  In  this  position  the  edges  are 
firmly  cemented  together  so  that  the  two  prints  can  not 
easily  be  displaced.  They  are  then  mounted  between  two 
plates  of  glass  and  placed  in  a  frame  or  case. 

In  order  to  succeed  you  need  not  be  afraid  of  laying  on 
too  much  color,  for  much  color  is  required  to  produce  a 
good  effect.  Pink  madder  will  give  the  face,  neck,  and 
arms  the  proper  tint ;  the  habiliments  will,  of  course,  re- 
ceive the  colors  belonging  to  them. 

The  Ivorytype,  by  Mb.  Wenderoth. 

Select  a  vigorous,  clearly-defined  impression,  with  margin 
enough  to  allow  for  mounting  upon  the  painter's  stretcher, 
or  painting-board.  Damp  the  print  with  a  sponge  dipped 
in  clear  water,  then  paste  its  edges  upon  the  stretcher,  and 
with  clean  paper  over  its  face,  rub  the  print  down  smoothly. 
When  dry  it  will  be  tight  and  firm  for  the  artist  to  operate 
upon.  Or  mount  it  upon  a  sheet  of  glass  with  its  edges 
ground  to  hold  the  paste. 

The  photograph  is  now  colored  upon  the  face  as  a  minia- 
ture, with  permanent  colors,  but  colors  much  stronger  than 
those  commonly  employed  on  surface-painting,  as  the  man- 
ner of  mounting  the  complete  pictures  upon  plate-glass  has 
the  effect  of  lowering  the  tone  of  the  colors  used. 

As  transparent  colors  are  reduced,  or  lose  considerably 
in  tone  by  this  mode  of  mounting,  they  should  be  painted 
in  much  more  strongly  than  for  surface-painting  ;  while 
the  body  colors  should  be  kept  down  or  reduced  in  tone, 
since  they  are  heightened  or  made  more  brilliant  and  vig- 
orous by  the  manner  of  mounting. 

The  colored  print  is  now  mounted  on  a  perfectly  clean 
sheet  of  plate-glass,  face  downward,  as  follows :  Melt 
bleached,  pure  white  wax,  and,  while  hot,  pour  it  upon  the 
glass  plate,  which  is  also  made  and  kept  hot  on  a  steel  or 
iron  plate,  or  a  soapstone  slab,  under  which  one  or  two 
spirit-lamps  are  continuously  burning.  While  the  wax  is 
quite  liquid  take  the  print  by  the  ends,  spring  it  in  the  mid- 
dle, and  lower  it  gently  into  the  heated  wax,  carefully 
pressing  from  the  middle  outward  both  parts  of  it  down 
into  the  wax,  and  then  with  a  straight-edged  paper-folder 
of  ivory  or  bone,  or  some  similar  article  suited  to  the  pur- 
pose, press  and  work  out  all  the  air-bubbles  and  superfluous 


REDUCTION  OF  WASTE  RESIDUES 


421 


wax.  This  operation  must,  of  course,  be  executed*  while 
the  plate  is  quite  warm. 

The  paper-folder  should  be  carefully  rubbed  from  one 
extremity  of  the  print  to  the  other  without  lifting  it  there- 
from or  suspending  the  process,  as  a  mark  would  thus  be 
left  on  the  picture,  which  will  be  thoroughly  saturated  with 
wax,  and  which,  if  properly  handled,  will  be  transparent, 
smooth,  and  beautiful. 

Some  artists  use  a  compound  of  one  part  gum  dammar  to 
eight  parts  wax ;  or  Canada  balsam  and  wax ;  or  gum  elami 
and  wax,  in  the  proportion  of  one  to  eight  parts  of  wax. 
Others  use  a  larger  proportion  of  the  gum  varnishes. 

Finally  the  picture  is  finished  by  placing  upon  its  back 
and  firmly  sealing  to  the  glass  a  clean  sheet  of  white  paper 
or  cardboard,  with  a  cardboard  border  or  mat  between  the 
picture  and  the  paper,  and  with  small  lumps  of  hard  wax 
stuck  upon  the  dark  or  opaque  parts  of  the  picture,  *so  ar- 
ranged as  to  keep  them  about  one  sixteenth  or  one  twentieth 
of  an  inch  asunder.  This  distance  must  be  determined  by 
effect  or  appearance  produced,  and  regulated  by  the  judg- 
ment of  the  artist,  when  the  picture  is  ready  for  the  frame. 
Sometimes  a  duplicate  tinted  print  of  the  face  is  placed  be- 
hind to  give  more  color-vigor. 

To  produce  this  picture  in  its  perfection  requires  the 
highest  degree  of  artistic  skill. 

What  to  do  with  Waste  Residues  of  Silver  and  Gold. 
Silver  in  an  Old  Nitrate  of  Silver  Bath. 

From  the  fact  that  an  old  nitrate  of  silver  bath  contains 
several  other  compounds  besides  that  of  silver,  such  as  ni- 
trate of  the  oxide  cadmium,  of  soda,  of  lithia,  of  ammo- 
nia, of  potassa,  etc.,  the  first  part  of  the  process  consists  in 
separating  the  silver  compound  from  the  rest.  This  can  be 
effected  easily  in  two  different  ways : 

First  Method. — Decompose  the  bath  solution  by  a  solu- 
tion of  common  salt,  which  produces  the  insoluble  chloride 
of  silver  in  the  form  of  a  white  deposit.  Continue  to  add 
of  the  salt  solution  as  long  as  any  white  precipitate  is  pro- 
duced. Finally  allow  the  deposit  to  settle  and  then  pour 
off  the  supernatant  clear  liquid.  Now  throw  in  water  and 
stir  the  deposit  well  up,  and  set  the  mixture  aside  to  settle. 
When  the  chloride  has  thoroughly  settled,  pour  the  water 
off,  and  again  add  fresh  water.    Stir  the  mixture  up,  and 


422 


SEDUCTION  OF  WASTE  RESIDUES. 


again 'Set  it  aside  to  settle.  This  operation  of  washing  the 
chloride  can  be  repeated  several  times.  Finally  the  deposit 
is  poured  upon  a  sheet  of  thick,  white  blotting-paper  and 
set  aside  in  a  warm  place  to  dry.  Preserve  the  chloride  of 
silver  in  the  dark-room  until  a  sufficient  quantity  has  accu- 
mulated for  reduction. 

Second  Method. — Add  solution  of  caustic  potash  or  of 
lime  to  the  bath  as  long  as  there  is  found  a  brown  precipi- 
tate ;  then  set  the  mixture  aside  to  settle.  The  clear  liquid 
is  then  poured  off ;  to  this  a  few  drops  of  the  potash  or  lime 
solution  are  added  ;  if  no  brown-colored  precipitate  ensues, 
it  may  be  concluded  all  the  silver  has  been  precipitated  in 
the  form  of  oxide  of  silver.  The  latter  is  carefully  washed 
in  several  changes  of  water,  and  then  put  aside  to  dry. 
When  dry  it  is  placed  in  a  bottle  until  a  sufficient  quantity 
has  accumulated  for  reduction. 

Silver  in  the  Hyposulphite  of  Soda  Bath. 

The  silver  in  the  fixing-bath  is  not  precipitated  by  either 
a  soluble  chloride  or  by  an  alkali.  Use,  therefore,  a  current 
of  sulphureted  hydrogen  gas,  or  pour  into  the  bath  a  solu- 
tion of  a  soluble  sulphide,  such  as  sulphide  of  potassium 
or  sulphide  of  ammonium.  Continue  the  gas  or  the  addi- 
tion of  the  sulphide  as  long  as  a  black  precipitate  is  formed ; 
this  precipitate  is  well  washed  in  several  changes  of  water 
on  a  filter,  after  which  it  is  dried  and  preserved  for  reduc- 
tion. 

Silver  in  the  Washings. — The  washings  may  be  thrown 
into  a  large  tank  containing  either  pieces  of  copper  plates 
and  copper  clippings,  or  a  solution  of  salt.  In  the  first  case 
the  silver  will  be  reduced  to  the  metallic  condition  in  the 
state  of  a  fine  powder,  which  maybe  collected,  washed,  and 
dissolved  in  nitric  acid ;  in  the  second  case,  that  is,  with  a 
solution  of  salt,  the  silver  will  be  precipitated  as  chloride, 
which  at  given  intervals  is  collected  and  thoroughly  washed 
on  the  filter.  It  is  then  added  to  the  chloride  of  silver  ob- 
tained from  the  other  residues. 

Silver  in  the  Paper  Clippings,  etc. — Take  a  clean  chafing- 
dish,  or  a  small  stove  from  which  all  the  ashes  have  been 
carefully  brushed  away.  Make  a  small  pile  of  the  waste 
silvered  paper  and  set  it  on  fire ;  while  the  fire  is  burning 
keep  adding  more  and  more  of  the  paper,  until  the  stock 
of  paper  becomes  exhausted.  See  that  every  part  of  the 
paper  has  been  thoroughly  converted  into  ashes,  and  that 


REDUCTION  OF  WASTE  RESIDUES. 


423 


the  draft  is  not  so  strong  as  to  carry  them  up  the  chimney. 
Collect  all  the  ashes  and  preserve  them  likewise  for  reduc- 
tion. 

It  is  thus  evident  we  obtain  apparently  four  different  sorts 
of  silver  powder.    Let  us  examine  them : 
The  first  is  Chloride  of  Silver. 
The  second  is  Oxide  of  Silver. 
The  third  is  Sulphide  of  Silver. 

The  fourth  is  Oxide  of  Silver,  together  with  the  mineral 
impurities  in  the  paper  itself,  such  as  lime,  etc. 

The  latter  may  be  reduced  to  a  pure  state,  either  as  chlor- 
ide or  oxide,  by  first  dissolving  it  by  nitric  acid,  and  then 
decomposing  the  impure  nitrate  of  silver  either  by  a  solu- 
tion of  common  salt,  and  thus  obtaining  the  silver  as  chlor- 
ide ;  or,  secondly,  by  a  solution  of  caustic  potash,  lime,  etc., 
which  precipitates  the  silver  as  oxide.  In  either  case  the 
precipitate  is  carefully  washed  as  before  described,  and  then 
mixed  either  with  the  pure  chloride  or  oxide  as  the  case 
may  be. 

The  next  operation  is  to  reduce  these  deposits  either  into 
pure  silver  or  directly  into  nitrate  of  silver.  There  are 
various  ways  of  doing  this  work. 

Reduction  of  the  Chloride  and  Sulphide  into  Pure  Silver. 

Put  these  ingredients  all  together,  and  add  to  them 
twice  their  weight  of  dry  saltpetre  ;  mix  them  intimately. 
Into  a  crucible  raised  to  and  maintained  at  a  red  heat, 
throw  in  a  spoonful  of  the  mixed  powder  at  a  time  ;  after 
each  combustion  keep  adding  spoonful  by  spoonful  of  the 
powder  until  the  whole  mass  has  thus  been  ignited  and, 
so  to  say,  burned.  The  nitrate  of  potash  (saltpetre)  is 
easily  decomposed  by  heat,  and  gives  up  its  oxygen  to  the 
silver  in  the  chloride  and  sulphide  ;  but  the  oxide  of  silver 
is  reduced  to  pure  silver  very  easily  by  heat  alone.  The 
crucible  finally  is  allowed  to  cool,  and  then  it  is  filled  with 
water,  which  dissolves  the  soluble  salt,  the  chloride,  and 
sulphide  of  potassium,  and  perhaps  a  small  portion  of  sul- 
phate of  potassa.  The  insoluble  part  of  the  fused  mass 
will  consist  of  pure  silver  in  a  sponge-like  form,  or  in  fine, 
isolated,  minute  grains.  These  may  be  collected  and 
either  fused  into  a  solid  mass,  or  dissolved  in  pure  nitric 
acid,  so  as  to  form  nitrate  of  the  oxide  of  silver. 

The  reduction  of  the  oxide  of  silver  requires  no  addition 
of  saltpetre ;  heat  alone  will  be  sufficient. 


424 


REDUCTION  OF  WASTE  RESIDUES. 


It  may  happen,  and  that  frequently,  that  the  operator 

has  got  neither  a  crucible  nor  a  furnace  to  heat  it  conven 
iently.  In  this  case,  mix  the  chloride,  sulphide,  and  oxide 
of  silver,  and  weigh  the  mixture  ;  weigh  out  an  equal 
amount  of  fine,  dry  sawdust,  twice  the  amount  of  saltpetre, 
and  twice  the  weight  of  sulphur ;  mix  all  these  ingredients 
intimately  together.  Of  course  these  articles  must  be  all 
perfectly  dry.  This  mixture  is  a  sort  of  slow  gunpowder  ; 
slow,  because  the  sawdust  is  not  yet  charcoal.  Now  take 
a  piece  of  dry  wood  a  couple  of  inches  thick  and  a  foot 
square.  Place  a  spoonful  of  the  mixture  on  the  middle 
and  ignite  it ;  keep  adding  more  as  the  combustion  pro- 
ceeds, until  all  of  the  mixed  powder  has  been  deflagrated. 
By  this  proceeding  the  silver  compounds  are  reduced  into 
a  spongy  mass  of  pure  silver,  which  may  be  separated  from 
all  extraneous  matters  by  washing  in  water  and  then  dis- 
solved in  nitric  acid.  The  sulphur  maybe  omitted  if  a  red- 
hot  plate  of  iron  or  an  iron  ladle  be  substituted  for  the 
block  of  dry  wood.  But  in  this  case  the  iron-plate  must 
be  maintained  at  a  red-heat  all  the  while,  that  is,  until  the 
mixed  powder  no  longer  burns,  but  settles  down  into  a 
fused  mass,  which  contains  the  silver  in  a  minute  granular 
or  spongy  form. 

Another  Mode  of  Treating  the  Silver  Compounds. 

Collect  all  the  oxide  and  chloride  of  silver  as  obtained 
from  the  various  residues,  and  dissolve  them  in  ammonia  ; 
afterward  pass  a  current  of  sulphurous  acid  through  the 
solution  as  long  as  a  precipitate  is  formed.  This  precipi- 
tate is  metallic  silver  in  a  state  of  fine  division.  After  a 
thorough  washing  on  the  filter,  it  may  be  dissolved  in  ni- 
tric acid  for  use. 

Sulphurous  acid  for  this  experiment  may  be  easily  pre- 
pared by  decomposing  sulphuric  acid  by  means  of  small 
chips  of  dry  beach  wood  placed  in  a  retort,  or  flask,  fur- 
nished with  a  glass  tube  bent  at  right  angles  and  dipping 
into  the  silver  solution.  Heat  being  applied  to  the  vessel, 
sulphurous  acid  is  disengaged. 

Instead  of  using  sulphurous  acid  for  this  purpose,  sul- 
phite of  ammonia  may  be  mixed  with  the  dissolved  silver ; 
the  result  will  be  the  same. 

For  further  information  on  this  subject,  illustrated  with 
cuts,  see  pages  433  to  438,  inclusive. 


COLLO-PROTOSTTLPHATE  OF  IRON  DEVELOPER.  425 


COLLO-PROTOSULPHATE  OF  IRON  DEVELOPER. 

The  new  developer  of  M.  Carey  Lea,  M.D.,  which  con- 
tains in  addition  to  the  iron-salt,  a  quantity  of  gelatine,  or 
a  gelatine  compound,  has  occupied  the  attention  of  photo- 
graphers lately  to  a  considerable  extent.  The  gelatine,  or 
gelatine  compound,  acts  as  a  restrainer  to  the  developing 
action  of  the  iron  salt.  It  appears,  also,  to  form  a  new 
compound  with  the  silver  salt  during  the  reduction  or  de- 
velopment, an  organic  precipitate  mixed  along  with  the 
reguline  reduction,  or  perhaps  a  new  silver  compound. 
The  gelatine  does  still  more  than  this  ;  it  causes  the  devel- 
oper to  flow  over  the  plate  smoothly  and  evenly,  and  thus 
requires  no  longer  any  alcohol  ;  and  furthermore,  the 
whole  amount  of  intensity  can  be  obtained,  as  the  doctors 
say,  by  the  first  intention,  that  is,  without  any  re-develop- 
ment or  intensification. 

Our  own  experience  indicates  that  this  developer  re- 
quires an  exposure  slightly  longer  than  the  ordinary  devel- 
oper ;  but  this  is  really  no  drawback  to  its  merits  ;  it  is 
rather  an  advantage,  because  it  allows  the  developer  time 
to  bring  out  the  middle  tones  which  frequently  are  entirely 
lost  sight  of.  With  the  ordinary  developer,  and  the  old 
mode  of  intensifying  with  a  silver  solution,  the  prints  gen- 
erally exhibit  nothing  more  than  the  extremes  of  light  and 
shade ;  the  soft  gradations  are  lost  sight  of. 

The  author  gives  two  methods  of  preparing  this  devel- 
oper ;  but  gives  a  preference  to  the  latter  of  the  two. 

1.  u  Let  an  ounce  of  good  gelatine  soak  and  swell  in  two 
ounces  of  water.  Apply  a  gentle  heat,  (very  gentle,)  and 
when  solution  is  complete,  add  five  fluid  drachms  of  sul- 
phuric acid.  Stir  the  mixture  very  thoroughly,  pouring  in 
the  acid  by  degrees,  and  keeping  the  fluid  actively  agitated 
all  the  while.  Combination  begins  to  take  place  at  once  ; 
the  gelatine  becomes  a  mere  fluid,  and  acquires  a  very  pe- 
culiar odor.  Set  the  vessel  aside  for  twelve  hours,  to  let 
the  combination  of  the  acid  and  gelatine  become  complete, 
and  then  add  iron  filings  in  excess.  The  conjugated  acid 
saturates  itself  with  iron  far  more  slowly  than  does  simple 
sulphuric  acid.  The  mixture  should  also  be  diluted  with 
its  own  bulk  of  water,  and  be  set  in  a  cool  place  and  occa- 
sionally stirred.  In  two  or  three  days  the  acid  will  be  sat- 
urated. To  be  sure  no  free  sulphuric  acid  shall  be  present, 
throw  in,  just  before  filtering,  a  little  acetate  of  soda,  (half 


426 


THE  COLLO-FERRIC  DEVELOPER. 


a  drachm  will  be  enough.)  Then  filter  and  dilute  to  fifteen 
ounces. 

2.  "  Add  an  ounce  of  sulphuric  acid  to  three  ounces  of 
water,  and  set  aside  to  cool.  Then  add  to  this  liquid  an 
ounce  of  good  gelatine  ;  let  it  swell  and  dissolve,  placing  it 
for  that  purpose  in  a  slightly  warm  place,  not  exceeding 
blood  heat,  for  twenty-four  hours.  Then  add  iron  filings  in 
excess,  avoiding  all  application  of  heat ;  let  it  stand  for  sev- 
eral days.  Finally  add  a  little  acetate  of  soda  as  before  ; 
filter,  and  dilute  to  fifteen  ounces." 

Modification  of  the  Collo-ferric  Developer. 

Several  modifications  of  the  preceding  developer  have 
been  made  by  different  amateurs,  (very  few  of  the  practical 
photographers  having  taken  it  up  ;)  the  one  by  Mr.  Cherrill 
is  excellent.  The  following,  however,  is  still  superior,  the 
object  being  to  get  a  developer  that  will  fulfill  all  the  re- 
quirements regardless  of  expense.  We  think  we  have  suc- 
ceeded in  our  aim. 

Prepare  in  the  first  place  the  following  solution,  and  keep 
it  in  stock : 

Formula  for  the  Restrainer. 


Sulphuric  acid,   1  ounce. 

Nitric  acid,   4  drachms. 

Acetic  acid,  (glacial,)   1  ounce. 

Alcohol,   1  ounce. 

Gelatine,   2  drachms. 

Ammonia,  (concentrated,)   6  ounces. 

Water,   2f  ounces. 


Mix  the  sulphuric  acid  with  one  ounce  of  the  water,  and 
allow  the  mixture  to  cool ;  then  add  the  gelatine,  and  let  it 
dissolve.  Neutralize  the  solution  with  the  six  ounces  of 
ammonia,  (more  or  less  as  may  be  required  according  to, 
circumstances.)  Stir  the  solution  well  after  each  addition 
of  the  ammonia,  and  introduce  a  piece  of  litmus  paper.  As 
soon  as  the  latter  begins  to  turn  blue  again,  cease  to  intro- 
duce any  more  ammonia.  Finally  add  the  remaining  part 
of  the  water,  the  alcohol,  the  nitric  and  acetic  acids. 

Developer. 

Protosulphate  of  iron,  88  grains. 

Water,   4  ounces. 

Restrainer,  2  drachms. 

There  is  more  appearance  of  trouble  in  the  formula  than 
there  is  in  reality  in  its  preparation ;  and  when  once  pre- 


PHOTO-MEZZOTINT  PRINTING. 


427 


pared,  there  is  sufficient  to  make  up  at  least  two  hundred 
ounces  of  an  excellent  developing  solution  that  produces  all 
the  intensity  required. 

Photo-Printing. 

One  of  the  most  decided  improvements  and  advances 
in  photography  is  the  discovery  made  simultaneously  by 
Joseph  W.  Swan,  Esq.,  and  Walter  Woodbury,  Esq.,  by 
which  plates  impressed  with  a  reverse  photographic  image 
can  be  printed  from  with  the  same  facility  as  a  copper-plate 
engraving.  Hitherto,  it  has  been  impossible,  not  to  prepare 
a  photo-electrotype  plate  or  stone,  but  when  prepared,  to 
obtain  satisfactory  impressions  from  such  a  plate  or  stone. 
The  defect  of  all  such  prepared  plates  was  the  total  absence 
of  granulation  in  the  deep  shades,  by  means  of  which  the 
printing-ink  is  retained  in  its  place,  and  without  which  all 
attempts  to  print  such  surfaces  as  the  regular  gradations  of 
light  into  shade  in  the  human  face,  or  on  a  smooth  marble 
pillar  were  found  futile.  Both  the  gentlemen  above-men- 
tioned have  succeeded  in  a  most  satisfactory  manner  to  ac- 
complish this  difficult  task  ;  and  photo-mezzotint,  or  photo- 
relief  printing,  will  soon  be  one  of  our  means  of  illustrating 
our  conceptions  and  instructions  with  photographic  prints. 

Swarfs  Photo- Mezzotint  Printing* 

Mr.  Swan  makes  use  of  the  bichromated  gelatine  tissue, 
whose  preparation  is  described  in  the  preceding  article  on 
the  Carbon  Process.  A  piece  of  this  tissue  is  exposed  be- 
neath a  negative  in  the  pressure-frame  to  sunlight  for  the 
proper  length  of  time.  It  is  then  taken  into  the  dark-room, 
and,  removing  it  from  the  frame,  its  impressed  side  is 
cemented,  by  means  of  a  solution  of  India-rubber,  to  a  piece 
of  glass.  As  soon  as  the  cement  is  dry,  the  glass  with  its 
gelatine  film  is  immersed  in  a  dish  of  warm  water,  where  it 
remains  until  all  the  soluble  portions  of  the  gelatine  are  dis- 
solved. The  action  of  light  upon  the  bichromated  gelatine 
film  is  of  such  a  nature  as  to  render  all  those  parts,  upon 
which  it  impinges,  insoluble  ;  while  the  other  parts  remain 
soluble.  The  insolubility  is  in  exact  ratio  with  the  actinic 
impression,  so  that,  where  the  light  meets  with  the  least  ob- 
struction in  passing  through  the  negative,  it  will  penetrate 
deeper  into  the  gelatine  film  and  indurate  it,  or  at  least  ren- 
der it  insoluble.  When  the  soluble  parts,  therefore,  are 
removed^  the  back  surface  of  the  tissue  will  exhibit  a  sort 
20 


428 


PHOTO-MEZZOTINT  PRINTING. 


of  relief,  the  deep  shades  standing  out  brightest,  while  the 
lights  scarcely  exhibit  any  gelatine  at  all. 

The  next  operation  consists  in  obtaining  an  electrotype 
reverse  of  this  relief  picture  in  gelatine,  and  also  to  do  this 
while  the  film  is  still  wet  and  in  an  expanded  or  swollen 
condition.  In  the  first  place  the  picture  is  surrounded  with 
a  metallic  wire  along  the  edge,  by  which  it  can  be  brought 
into  metallic  contact  with  the  electrolytic  solution  and  the 
negative  pole  of  a  galvanic  battery.  The  picture  is  now 
covered  with  silver  solution  or  silver  powder.  The  plate  is 
now  put  into  the  copper  solution,  and  the  battery  poles  are 
properly  attached.  In  this  solution  the  plate  remains  until 
the  copper  deposit  is  sufficiently  thick  and  strong  to  be  re- 
moved. The  copper  plate  thus  formed  is  finally  lifted  up 
from  the  gelatine,  backed  up  and  mounted  on  a  flat  block 
for  printing  from.  This  plate  has  considerable  resemblance 
to  an  ordinary  engraved  copper-plate  ;  but  to  a  practical 
engraver  there  is  an  essential  difference,  which  to  him  is 
very  perceptible  ;  it  contains  no  granular  points  or  crossed 
lines  in  the  deep  and  broad  surfaces  which  correspond  to 
the  shadows  of  the  picture  ;  and  to  obtain  impressions  from 
such  plates  is  the  great  discovery  which  Swan  denominates 
Photo-Mezzotint  printing  or  engraving. 

In  the  ordinary  copper-plate  the  oily  carbonaceous  ink  is 
filled  in  and  loaded  upon  the  surface,  the  excess,  over  and 
above  that  which  can  be  retained  in  the  crevices  and  aper- 
tures, being  carefully  cleaned  off ;  but  if  the  same  mode 
were  employed  to  ink  the  photo-electrotype,  the  ink  would 
nearly  all  be  rubbed  off.  Hence  an  entirely  new  plan  of 
inking  the  plate  is  adopted.    The  following  is  the  plan  : 

The  ink  used  in  this  process  is  a  warm  solution  of  gela- 
tine colored  with  carbon  or  any  other  convenient  coloring 
matter.  The  plate  is  first  slightly  greased,  and  then  the  ink 
is  applied  to  the  plate  so  as  to  cover  it  The  paper  prepared 
for  the  purpose  is  laid  upon  the  ink  and  pressed  down  upon 
it  with  a  perfectly  level  and  almost  unyielding  plate  of 
metal,  stone,  etc.  It  is  evident  that  the  paper,  being  thus 
forcibly  pressed  into  contact  with  the  copper-plate  below, 
will  press  out  all  excess  of  ink,  and  leave  only  that  portion 
which  fills  the  reverse  relief  that  forms  the  picture.  The 
ink  soon  congeals  or  sets,  when  the  paper  may  be  lifted  up 
from  the  plate,  carrying  with  it  the  congealed  gelatine.  At 
this  stage  the  ink  stands  out  in  relief,  and  conspicuously  so 
in  the  deepest  shadows ;  in  the  lights  the  gelatine  has  all 
been  pressed  out  from  between  the  paper  and  the  j>late  ;  so 


PHOTO-RELIEF  PRINTING. 


429 


that  the  variation  of  tone  in  the  picture  depends  entirely 
upon  the  thickness  of  the  colored  him,  and  ranges  between 
the  absence  of  film  to  the  extreme  depths  of  the  shadows. 

The  impression  thus  obtained,  as  is  evident,  will  be  a  fac- 
simile of  the  original  bichromated  gelatine  picture  obtained 
beneath  the  negative.  The  relief,  which  at  the  first  is  mani- 
fest, disappears  as  the  film  dries.  In  its  present  condition, 
the  gelatine  picture  is  soluble,  and  on  this  account  would  be 
liable  to  speedy  destruction  from  a  variety  of  causes.  The 
easiest  mode  of  rendering  gelatine  insoluble  is  to  immerse  it 
in  a  solution  of  alum  ;  the  prints  are  consequently  placed  in 
such  a  solution  and  afterward  washed  in  water ;  they  are 
then  dried,  cut,  and  mounted. 

The  operation  of  printing  with  a  proper  number  of  appro- 
priate presses  is  quite  rapid,  a  single  man  being  thus  capa- 
ble of  producing  a  thousand  prints  a  day. 

Photo-Relief  Printing. 

The  name  at  the  head  of  this  article  is  given  to  the  pro- 
cess of  obtaining  prints  from  an  intaglio  relief  in  metal  by 
Walter  Woodbury,  Esq.  This  process  is  in  no  respect  dif- 
ferent in  principle  from  from  the  Photo-Mezzotint  Printing 
by  Mr.  Swan  ;  but  the  modes  of  operation  are  in  some  re- 
spects different.  The  process  is  divided  into  three  parts  : 
firstly,  the  Preparation  of  the  Gelatine  Relief ;  secondly, 
the  Production  of  the  Metal  Intaglio  ;  and  thirdly,  the 
Printing  Operation  from  the  Metal  Intaglio. 

The  Preparation  of  the  Gelatine  Relief 

Take  a  number  of  thin  layers  of  mica  of  the  required  size 
and  uniform  in  thickness,  and  affix  them  by  moisture  to  a 
large  plate  of  glass.  When  the  excess  of  water  is  pressed 
from  beneath  the  micaceous  layers,  they  will  adhere  with 
considerable  tenacity,  and  admit  of  being  easily  cleaned  and 
polished  like  an  ordinary  plate  of  glass. 

The  bichromatized  gelatine  is  prepared  in  the  following 
manner :  "  Dissolve  four  ounces  of  Nelson's  opaque  gelatine 
in  twenty  ounces  of  water  ;  clarify  with  white  of  egg,  and 
filter.  To  four  ounces  of  this  solution  add  sixty  grains  of  bi- 
chromate of  ammonia,  dissolved  in  half  an  ounce  of  warm 
water  and  a  small  quantity  of  Prussian  blue.  This  serves 
to  give  the  finished  relief,  a  color  by  which  to  judge  of  its 
printing  qualities,  and  does  not  interfere  with  the  action  of 
the  light  in  penetrating  the  gelatine."  The  ingredients  are 


430 


PHOTO-RELIEF  PRINTING. 


intimately  mixed  together ;  the  mixture  is  then  filtered 
through  muslin,  and,  whilst  still  warm,  is  poured  in  suffi- 
cient quantity  upon  the  plates  of  mica  (the  plate  of  glass  to 
which  they  adhere  having  previously  been  placed  on  a 
leveling-stand)  so  as  to  cover  the  whole  to  incipient  run- 
ning over.  In  this  condition  (the  operation  of  course  hav- 
ing been  performed  in  the  dark-room)  the  plate  is  left  in  a 
warm  place  to  set.  As  soon  as  the  gelatine  tissue  is  suffi- 
ciently dry,  it  is  cut  through  along  the  edges  of  each  layer  of 
mica  to  the  glass  plate  beneath ;  and,  by  raising  one  corner 
with  the  knife-blade,  each  layer  of  mica  may  thus  be  strip- 
ped from  the  glass  plate.  Place  each  of  the  layers  of  gela- 
tine tissue  on  a  piece  of  blotting-paper  of  the  same  size,  and 
clean  the  surface  of  the  mica.  The  latter  is  now  placed  in 
contact  with  a  negative,  and  a  piece  of  glass  is  placed  be- 
hind on  the  blotting-paper  and  submitted  to  pressure  in 
the  printing-frame.  The  light  of  the  sun  is  concentrated 
by  passing  through  a  condensing  lens.  After  exposure  for 
one  or  two  hours,  according  to  the  intensity  of  the  light 
and  the  opacity  of  the  negative,  the  gelatine  film  is  placed 
in  a  dish,  and  hot  water  is  poured  upon  it  until  all  the 
soluble  parts  have  been  dissolved  and  removed.  The  relief 
picture  is  then  allowed  to  dry  at  a  gentle  heat.  When 
nearly  dry,  the  film  is  removed  from  all  artificial  heat,  and 
allowed  to  dry  spontaneously,  otherwise  the  gelatine  would 
be  apt  to  split  from  the  plates  of  mica.  As  soon  as  the  film 
is  quite  dry,  the  plate  is  put  away  between  the  leaves  of  a 
book  until  it  is  required  for  the  next  operation. 

Production  of  the  Metal  Intaglio. 

A  sheet  of  soft  metal,  a  mixture  of  lead  and  type-metal, 
with  perfectly  smooth  surfaces,  is  placed  upon  a  rigid  and 
smooth  plane  of  steel ;  over  the  soft  metal  is  laid  the  hard 
gelatine  print  face  downward  ;  and  finally  over  this  is  laid 
another  rigid  and  smooth  plane  of  steel.  This  combination 
is  subjected  to  a  pressure  of  four  tons  to  each  square  inch 
of  surface.  Although  our  first  conceptions  would  be  that 
the  gelatine  picture  would,  by  this  pressure,  be  crushed  or 
flattened,  the  result  is  a  perfectly  sharp  and  accurately  de- 
fined metal  reverse  of  the  gelatine  picture.  This  operation 
is  the  effect  of  a  moment's  labor.  Other  metal  intaglios 
may  be  obtained  from  the  same  gelatine  picture  in  case  it 
is  necessary  to  print  with  a  number  of  presses  at  the  same 
time. 


THE  F0XTYPE. 


431 


Printing  Operation  from  the  Metal  Intaglio. 

The  ink  consists  of  a  thick  and  warm  solution  of  gelatine, 
colored  to  any  tint  desired.  The  author  of  the  process  finds 
that  the  water-colors  sold  in  tubes  are  the  most  suitable,  as 
these  can  be  mixed  directly,  and  the  quantity  can  easily  be 
measured.  Lampblack  tinged  with  various  proportions  of 
crimson  lake  yields  a  variety  of  fine  tones. 

The  press  used  by  Mr.  Woodbury  consists  of  a  shallow 
box  with  an  extra  and  movable  bottom  supporting  a  strong 
plate  of  glass.  The  plate,  by  means  of  four  screws  beneath, 
can  be  raised  and  leveled  as  required.  The  metal  intaglio 
is  placed  on  the  plate  of  glass.  Another  strong  plate  of 
glass  is  fixed  in  the  under  side  of  the  lid  of  the  box,  and 
can  be  depressed  and  raised  by  hinges  on  one  side. 

The  lower  plate  is  now  raised  and  leveled  so  that  the 
upper  surface  of  the  metal  intaglio  is  in  accurate  contact 
with  the  lower  surface  of  the  upper  plate  of  glass  in  the  lid 
of  the  box.  This  adjustment  being  complete,  the  lid  is 
folded  back,  and  sufficient  of  the  melted  ink  is  poured  upon 
the  metal  intaglio  so  as  to  cover  it,  or  nearly  so.  The  pa- . 
per  is  now  laid  upon  the  ink,  and  the  lid  is  brought  down 
into  contact  with  the  paper,  and  bolted  down  for  a  minute 
or  so,  according  to  the  setting  property  of  the  gelatine. 
On  raising  the  lid,  the  paper  may  be  lifted  up,  and  along 
with  it  the  ink  in  relief. 

FOXTYPE. 

This  printing  process  has  been  patented  in  Great  Britain 
by  the  discoverer  Thomas  Fox,  Esq.  Ordinary  unsalted  pa- 
per is  used ;  and  a  transparent  positive  is  required,  because 
the  action  of  the  light  is  the  reverse  of  that  in  the  ordinary 
process : 

Sensitizing  Solution. 

Bichromate  of  potassa,  1  drachm. 

Sulphate  of  copper,  2  drachms. 

Water,  4  ounces. 

Float  the  papers  on  this  solution  for  four  or  five  minutes, 
and  then  hang  them  up  to  dry  either  spontaneously  or  by 
artificial  heat. 

When  dry,  place  the  paper  on  the  transparent  positive, 
and  submit  it  to  the  action  of  light  as  you  would  if  a  nega- 
tive were  used.  The  time  of  exposure  is  about  two  or 
three  minutes. 


432 


selle's  intensifying  solution. 


Development  of  the  Picture. 

Boil  the  shavings  of  logwood  in  water  for  a  couple  of 
hours  ;  the  decoction  is  then  filtered  and  used  hot. 

Float  the  pictures  on  this  solution  until  they  are  suffi- 
ciently intense  and  the  detail  is  all  out.  Next  immerse 
them  in  a  hot  solution  of  alum,  which  removes  the  yellow 
color  from  the  lights.  They  are  finally  well  washed,  dried, 
and  varnished. 

Different  shades  of  color,  from  blue,  purple,  light  black, 
and  deep  black,  can  be  obtained  by  varying  the  strength  of 
the  sensitizing  solution,  as  also  the  decoction  of  logwood. 

Selle's  Intensifying  Solution. 

This  intensifier  has  been  very  satisfactory  in  our  hands. 
It  produces  a  brownish-red  film  when  applied  to  the  nega 
tive  after  development. 

Dissolve  in  one  stock-bottle  twenty  grains  of  ferridcyan- 
ide  of  potassium  in  two  ounces  of  water. 

In  another  similar  bottle  dissolve  twenty  grains  of  sul- 
phate of  uranium  in  two  ounces  of  water. 

While  the  negative  is  still  moist,  (after  development,  fix- 
ing, and  washing,)  mix  a  drachm  of  each  of  the  preceding 
solutions,  and  pour  the  mixture  over  the  negative.  Keep 
the  solution  in  motion  until  the  proper  degree  of  intensity 
is  attained ;  finally  pour  off  the  residue,  and  wash  the  film. 

The  Aniline  Printing  Process. 

This  process  is  a  discovery  of  Mr.  Wm.  Willis.  A  trans- 
parent positive  is  used  in  the  operation. 

Preparation  of  the  Paper. 

Unsalted  and  plain  paper  is  floated  on  the  following  solu- 
tion, in  the  usual  way. 

Sensitizing  Solution. 

Bichromate  of  potassa,  5  drachms. 

Phosphoric  acid,  100  grains. 

Water,  10  ounces. 

After  floating  for  two  minutes,  hang  up  the  paper  to  drain 
and  dry. 


THE  ANILINE  PROCESS  PHOTOGRAPHIC  RESIDUES.  433 


Exposure. 

This  paper  is  more  sensitive  than  the  ordinary  silver- 
paper.  Expose  to  the  rays  of  the  sun  for  a  few  minutes, 
(from  two  to  ten)  and  to  diffused  light  from  a  quarter  to 
half  an  hour.  The  picture  becomes  visible  by  light  alone, 
if  exposed  long  enough. 

Development 

Cover  the  bottom  of  a  flat  dish  with  the  following 
solution : 

Commercial  aniline,  1  drachm. 

Benzole,  2  ounces. 

Develop  in  the  dark-room.  Attach  the  print  to  a  piece  of 
board,  and  expose  it  to  the  aniline  fumes.  The  latter  act 
upon  those  parts  that  have  not  been  affected  by  light,  and 
relatively  to  the  influence  of  the  shades  of  the  positive.  A 
variety  of  tones  can  thus  be  produced,  depending  upon 
the  proportion  of  free  acid  and  other  causes  not  yet  thor- 
oughly understood. 

Improved  Method  of  Treating  Wastes. 

Cut  your  prints  before  toning,  and  send  the  clippings 
with  your  silver  filters  in  bulk,  or  burn  them  in  an  old  iron 
pot,  or  other  vessel  (out  of  a  strong  draft),  and  pack  them 
separately.  Save  your  sink  wastes,  print-washings,  and 
collodion  skins  as  follows :  Place  two  half  barrels  or  buck- 
ets in  your  sink,  as  in  the  following  figure : 


434 


REDUCTION  OF  WASTE  RESIDUES. 


Develop  and  wash  lightly  over  tub  No.  1,  and  finish  wash- 
ing over  the  sink.  Pour  your  paper-washings  containing 
silver  into  No.  1,  adding  a  little  chloride  of  sodium,  or 
common  salt,  and  allow  the  water  to  pass  off  through  a 
pipe  placed  near  the  top  of  No.  2 ;  also  put  your  old  collo- 
dion skins  into  these  tubs.  Insert  a  spigot  two  inches 
from  the  bottom  of  No.  2,  in  order  to  draw  off  the  clear 
water  each  morning,  and  also  to  collect  the  deposits  when- 
ever desirable. 

Hypo.  Tonings,  when  no  longer  wanted  for  use,  should 
be  precipitated  with  sulphuret  of  potassium. 

Gold  Tonings  should  be  poured  into  a  large  bottle  or 
pitcher,  and  when  no  longer  required  they  may  be  precipi- 
tated with  protosulphate  of  iron.  Great  care  is  necessary 
in  the  precipitation;  for  if  too  much  salt  or  sulphide  be 
used,  the  silver  will  be  reduced  and  pass  off  into  the  water. 
This  method  of  saving  wastes  is  recommended  by  Mr.  Bur- 
well,  an  experienced  photographer,  of  the  Willard  Manu- 
facturing Company. 

The  Mast  Furnace  and  Rotating-Fan. 

There  are  three  different  furnaces  in  use  for  the  reduc- 
ing operations.  The  "Wind  Furnace,  in  which  the  draft 
of  the  chimney  alone  urges  the  fire ;  common  stoves  belong 
to  this  class.  If  properly  built,  and  provided  with  a  high, 
clean  and  unobstructed  chimney,  they  answer  tolerably 
well  for  reducing  operations.  The  Reverberatory  Furnace, 
in  which  the  flame  of  the  fire  is  condensed  and  reflected 
upon  the  fused  mass  by  a  funnel-shaped  dome,  which  will 
be  further  explained  on  another  page.  This  furnace  is 
best  adapted  for  the  reduction  of  gold  and  silver  wastes, 
giving  great  intensity  of  heat  with  continuity  of  action; 
and  lastly,  the  Blast  Furnace,  used  to  produce  a  quick  and 
intense  heat.  The  combustion  in  this  case  is  urged  by  a 
current  of  air,  forced  through  the  fire  by  means  of  a  bel- 
lows or  rotating-fan.  This  style  of  furnace  is  used  mostly 
in  the  refining  or  granulation  of  the  precious  metals.  An 
ordinary  small  cylinder  stove  may  be  readily  altered  into 
the  three  different  forms  above  mentioned.  When  used  as 
a  wind  furnace,  the  degree  of  heat  which  can  be  produced 
in  it  depends  upon  the  height  of  the  chimney  into  which 
the  flue  passes,  and,  as  a  general  rule,  the  higher  the 
chimney  the  greater  will  be  the  heat. 

It  is,  therefore,  preferable,  if  possible,  to  have  the  stove 


REDUCTION  OF  WASTE  RESIDUES. 


435 


placed  in  a  cellar,  or  at  least  on  the  lower  floor  of  a  build- 
ing. The  intensity  of  the  heat  may  also  be  vastly  increased 
by  so  proportioning  the  dimensions  of  the  furnace  and  the 
chimney  that  their  diameters  are  equal,  and  the  height  of 
the  chimney  be,  if  possible,  fifty  or  sixty  times  the  diameter 
of  the  body  of  the  furnace. 

By  following  these  directions  a  wind  furnace  of  the  best 
kind  can  be  obtained;  but  it  is  always  preferable  to  use  a 
reverberatory  or  blast  furnace,  especially  in  the  reduction 
of  paper  ashes  and  sulphide  of  silver.  The  first  being  dif- 
ficult of  fusion  on  account  of  the  large  amount  of  silicious 
and  carbonacious  matter  which  it  contains;  the  second 
being  one  of  the  most  obstinate  compounds,  in  regard  to 
perfect  reduction,  known  in  metallurgy. 

To  construct  a  furnace  on  the  reverberatory  principle, 
the  body  should  first  be  lined  with  a  thick  coating  of  re- 
fractory clay,  that  it  may  more  perfectly  withstand  the  in- 
tense heat  to  which  it  will  be  subjected. 

This  done,  the  orifice  on  the  back  of  the  stove,  intended 
to  receive  the  stove-pipe,  should  be  plastered  up  with  a 
thick  lump  of  fire-clay.  A  funnel-shaped  dome  with  an 
opening  at  the  top,  and  large  enough  in  diameter  to  fit 
tightly,  as  a  cover  on  the  top  of  the  stove,  should  be 
ordered  at  the  tinsmith's. 

Figure   1   represents  the  dome  Fig.  1. 

with  the  smoke-pipe  attached.  The 
pipe  should  be  self-supported,  so 
that  the  dome  may  be  lifted  on  or 
off  to  supply  fuel,  or  to  observe  the 
progress  of  the  operation. 

Figure  2  represents  this  arrange- 
ment complete.  A  is  the  cylinder 
stove,  of  which  the  smoke-pipe  B  is 
plugged  up  with  fire-clay;  C  is  the 
funnel-shaped  sheet-iron  dome,  ta- 
pering off  into  the  smoke-pipe  D; 
E  E  are  two  handles  which  may  be 
attached  to  the  dome  to  facilitate 
its  removal.  The  great  simplicity 
of  this  arrangement  can  be  seen  at  a  glance. 

A  Blast  Furnace  is  constructed  by  setting  a  cylinder 
stove,  with  smoke-pipe  attached,  in  the  ordinary  manner, 
closing  the  draft-hole  below  the  grate  with  a  piece  of 
sheet-iron,  having  a  circular  hole  large  enough  to  admit 
the  nozzle  of  a  pair  of  bellows,  or  rotating-fan  arrangement. 


436  REDUCTION  OF  WASTE  RESIDUES. 


Of  these  two  methods  of  creating  a  current  of  wind  we  de- 
cidedly prefer  the  latter. 

A  very  simple  and  efficient  rotating-fan  arrangement 
may  be  made  as  follows:  Take  a  ribbon-block,  two  inches 
in  diameter,  and  fasten  into  this  at  right-angles  four  sheets 
of  iron  or  stiff  pasteboard,  four  inches  wide  by  six  long,  or 
of  any  size  convenient  to  the  operator.  A  hole  should  be 
drilled  through  the  center  of  the 
block,  and  a  tightly-fitting  wooden 
axle  passed  through  it.  This  ar- 
rangement completed  should  be 
mounted  in  an  airtight  wooden 
box,  just  barely  large  enough  to  ad- 
mit of  its  turning  freely,  and  a 
crank  attached  outside  of  the  box 
to  one  end  of  the  spindle.  Two 
circular  holes,  about  three-quarters 
of  an  inch  in  diameter,  are  now  cut 
at  both  ends  of  the  box,  one  an  inch 
from  the  bottom,  and  the  other  an 
inch  from  the  top.  A  piece  of  iron 
gas-pipe,  about  six  inches  long, 
being  firmly  secured  in  the  lower 
hole,  the  arrangement  is  complete. 

Figure  3  represents  a  sectional 
view  of  this  wind  arrangement.  A  is 
the  ribbon-block  ;  BBBB  the  four 
sheet-iron  fans ;  C  the  spindle  upon 
which  the  whole  revolves;  D  the  wooden  encasement  into 
which  the  fan  arrangement  closely  fits;  E  represents  the 
crank,  allowed  to  pass  through  the  wooden  side  of  the  en- 
casement, and  by  which  the  fans  are  set  in  rotary  motion; 
F  the  circular  opening  at  the  back,  one  inch  from  the  top 
of  the  box;  Gr  the  orifice,  with  pipe  attached,  through 
which  the  air  is  forced  when  the  wheel  is  in  motion. 

When  the  fans  are  rapidly  turned  by  the  crank,  a  strong 
and  steady  current  of  air  is  forced  through  the  outlet. 
"When  it  is  required  to  use  the  blast,  the  outlet  tube  of  the 
fan  arrangement  is  allowed  to  project  through  the  circular 
hole  in  the  sheet-iron,  placed  before  the  draft-hole  of  the 
circular  stove,  and  the  connections  are  made  perfectly  air- 
tight by  a  lute  of  fire-clay  or  putty.  If  the  fan  is  now  set 
in  motion,  the  air  is  forced  through  the  fire,  causing  it  to 
burn  with  the  greatest  intensity.  The  power  of  this  little 
device  is  wonderful;  and  we  have  frequently  brought  a 


REDUCTION   OF  WASTE  RESIDUES. 


437 


mass  of  gold,  weighing  twenty  ounces,  to  thorough  fusion 
in  five  to  seven  minutes. 

"When  a  cylinder  stove  cannot  be  readily  obtained,  a 
very  cheap  and  efficient  furnace  may  be  put  together  as 
follows:  Take  a  piece  of  stove-pipe,  eight  to  ten  inches  in 
diameter  and  ten  to  twelve  inches  in  height,  and  line  it 
evenly  from  top  to  bottom  to  the  thickness  of  about  one 
inch  with  fire-clay,*  or,  in  default  of  this,  with  a  mixture 
of  equal  parts  of  kaolin  or  pipe-clay  and  fine  white  sand. 

This  mixture  should  be  made  into  an  even,  smooth  dough 
or  batter  with  water.  Previous  to  the  lining,  however,  a 
circular  hole  should  be  cut  large  enough  to  admit  the  noz- 
zle of  the  rotating-fan  arrangement,  and  about  one  inch 
from  the  bottom;  or  it  might  be  Y\g.  2. 

provided  with  a  small  door  to 
admit  the  draft,  if  used  as  a 
wind  or  reverberatory  furnace. 
This  being  done,  a  series  of 
short,  stout  pieces  of  wire,  from 
one-eighth  to  one-fourth  of  an 
inch  in  thickness,  should  be  em- 
bedded in  the  fire-clay,  about  an 
inch  from  the  draft-hole  to  serve 
as  a  grate.  For  convenience' 
sake,  three  sheet-iron  legs  should 
be  riveted  to  the  body  of  the 
furnace,  so  as  to  raise  it  six  to  eight  inches  from  the 
ground.  The  bottom  is  provided  with  a  movable  sheet- 
iron  cap,  like  those  on  blacking-boxes,  to  render  the  re- 
moval of  the  ashes  more  easy.  The  top  being  furnished 
with  a  movable  sheet-iron  dome  and  smoke-pipe,  commu- 
nicating with  the  chimney,  the  furnace  is  complete. 

This  simple  little  device  is  admirably  adapted  to  the 
wants  of  the  practical  photographer,  being  small,  neat, 
compact  and  very  efficient.  Used  in  connection  with  the 
wind  arrangement,  it  is  capable  of  melting  steel  in  from 
fifteen  to  twenty  minutes.  In  many  cases,  however,  it  may 
be  more  convenient  to  buy  a  complete  reducing  furnace. 
The  neatest  and  most  economical  of  the  ready  made  fur- 
naces is  that  known  as  Kent's,  which  has  all  the  appli- 
ances so  that  it  may  easily  be  changed  into  either  wind, 
blast  or  reverberatory  furnace. 

*  Fire-clay  of  the  consistency  of  thick  dough  may  be  obtained  at  any  fire* 
brick  factory. 


438 


REDUCTION   OF  WASTE  RESIDUES. 


Treatment  of  the  Cyanide  Fixing  Solution. 

It  has  been  generally  customary  to  throw  away  waste 
cyanide  fixing  solutions,  as  they  become  weak  by  use. 
They  contain,  however,  a  large  amount  of  silver,  which 
may  be  readily  and  economically  utilized.  The  precipita- 
tion of  silver  from  a  solution  of  its  cyanide  depends,  of 
course,  on  the  addition  of  a  reagent,  having  a  stronger 
chemical  affinity  for  the  silver  than  the  cyanic  acid  with 
which  it  is  combined  in  the  solution.  This  manipulation 
is  attended  with  considerable  danger,  owing  to  the  large 
amount  of  cyanic  acid  gas — a  most  potent  poison — which  is 
evolved  during  the  operation.  But  with  proper  manage- 
ment and  care,  not  only  the  silver,  but  the  active  principle 
of  the  cyanide  may  be  regained  from  such  waste  solutions. 

Take  a  wide-mouthed  bottle,  of  about 
two  quarts  capacity,  into  the  neck  of  which 
fit  a  smooth  and  very  tight  cork,  through 
which  pass  two  glass  tubes,  one  reaching 
within  a  few  lines  of  the  bottom  of  the 
B  |  u  ■  I  bottle  and  projecting  an  inch  over  the  cork, 
Sg  Jm  the  other  passing  only  about  half  an  inch 

V,  Gj  through  the  cork  and  bent  at  right-angles 

I  on  the  outside.    The  neck  of  a  small  fun- 
II  nel  is  secured  to  the  top  of  the  longest  tube 
B  by  means  of  a  little  wax.    Figure  4  repre- 
I  sents  this  arrangement.    A  second  bottle, 
MBBBI^B  wn^cn  may  ^e  about  half  the  size  of  the 
IBHBHBBI  former,  is  provided  with  a  tight  cork  and  a 
glass  tube  of  the  same  diameter  as  the  last  (which  should 
be  about  a  quarter  of  an  inch),  is  let  through  this  until  it 
reaches  within  the  fourth  of  an  inch  of  the  bottom,  and  like 
the  former  is  bent  at  right-angles.   Having  completed  this 
arrangement,  half  fill  the  first  bottle  with  the  waste  cyanide 
solution,  and  into  the  second  one  place  a  solution  consist- 
ing of — 

Pure  caustic  potash,  4  ounces. 

Water,  1  ounce. 

And  make  the  cork  and  joints  of  both  bottles  perfectly  air- 
tight by  brushing  over  the  following  mixture : 


Beeswax,  .... 

Resin, 

Turpentine, 

Vermilion,  enough  to  color. 


2  ounces. 
I  ounce. 
*  44 


Place  the  wax  and  resin  on  the  fire  in  a  tin  vessel,  and 


REDUCTION  OF  WASTE  RESIDUES. 


439 


when  thoroughly  melted  stir  in  the  turpentine  and  ver- 
milion. The  latter  is  only  for  appearance  and  may  be 
omitted. 

Figure  5  represents  the  complete  arrangement.  A  is 
the  larger  bottle  containing  the  waste  cyanide  solution;  B 
the  longer  tube  with  the  funnel  attached ;  C  the  shorter 
tube  connecting  with  the  rubber-pipe  D,  through  which 
the  cyanic  acid  gas  evolved  is  lead  by  means  of  the  glass 
tube  E  into  the  solution  of  pure  potash  F. 

Having  concluded  these  preliminary  arrangements,  com- 
mon hydrochloric  or  muriatic  acid  should  be  slowly  added 
to  the  cyanide  solution  in  the  larger  bottle  by  means  of  the 
small  funnel.  Upon  each  addition  of  the  acid  the  solution 
foams  and  seathes  violently,  and  care  should  be  taken  that 
it  does  not  boil  over.  Simulta 
neously  with  the  addition  of  the 
acid,  a  white  curdy  precipitate 
of  chloride  of  silver  is  formed, 
which,  however,  is  at  first  redis- 
solved  as  it  descends  into  the  so- 
lution. Acid  should  be  added  as 
long  as  it  occasions  the  slightest 
precipitate  or  foaming  in  the  so- 
lution, or  until  it  is  considerably 
in  the  access.  At  the  close  of  the 
operation  a  heavy  precipitate  of 
pure  chloride  of  silver  is  found 
in  the  first  bottle,  and  a  solution 
of  cyanide  of  potash  in  the  other.  If,  after  the  close  of  the 
operation,  the  solution  of  cyanide  of  potash  in  the  smaller 
bottle  should  be  somewhat  weak,  another  quantity  of  the 
cyanide  solution  may  be  treated  with  acid,  and  the  result- 
ing gas  allowed  to  pass  into  the  weak  liquid.  It,  however, 
generally  happens  that  the  fresh  cyanide  solution  obtained 
by  this  method  is  too  strong  for  photographic  purposes; 
in  that  case  it  may  be  simply  diluted  with  water.  This 
process  works  very  beautifully,  and  the  resulting  substan- 
ces are  nearly  chemically  pure.  When  it  is  desired  to  save 
the  silver  only,  the  waste  cyanide  solution  may  be  precipi- 
tated in  an  open  vessel  with  strong  hydrochloric  acid,  as 
before  mentioned;  but  the  operation  should  be  conducted 
in  an  open  place,  with  the  back  against  a  strong  draft  of 
wind,  so  that  the  poisonous  fumes  arising  may  be  carried 
away  from  the  operator.  We  would  recommend,  however, 
the  first  process  as  the  best,  having  used  it  with  great  sue- 


440 


REDUCTION  OF  WASTE  RESIDUES. 


cess  in  the  reductions  of  the  waste  cyanide  solutions  occur- 
ring in  the  electro-plating*  art. 

Another  very  excellent  method  of  utilizing  the  cyanide 
solutions,  is  to  evaporate  them  to  dryness.  By  these  means 
a  solid  is  obtained  (containing  all  the  silver),  which  may 
be  employed  with  the  greatest  success  as  a  flux  for  the  re- 
duction of  sulphide  of  silver  and  other  wastes.  In  evapor- 
ating the  solution  great  care  is  also  necessary,  as  fumes  of 
prussic  acid  are  given  off.  The  evaporation  should  be  con- 
ducted either  in  a  fireplace  or  in  the  open  air. 

Filtration  and  Decantation. 

The  mode  most  generally  resorted  to  for  the  separation 
of  precipitates,  from  liquids  in  which  they  are  suspended, 
is  that  of  filtration.  The  process  consists  simply  in  pass- 
ing the  substance  to  be  operated  upon  through  some  me- 
dium, fine  enough  to  intercept  any  solid  particles,  however 
finely  divided,  still  of  sufficient  porosity  to  allow  water  to 
pass  through  readily.  Paper  is  the  substance  most  gener- 
ally used  for  this  purpose.  The  paper  best  adapted  for  the 

filtration  of  the  bulky 
and  heavy  gold  and  sil- 
ver precipitates,  is  that 
known  as  German  filter- 
ing paper,  which,  besides 
being  very  strong  in  tex- 
ture, allows  the  water  to 
run  through  very  rapidly. 
"When  a  precipitate  is  of 
a  bulky  nature,  and,  es- 
pecially if  accompanied 
by  much  water,  a  plaited 
filter  should  be  made  use  of,  as  it  prevents  a  close  adhesion 
of  the  paper  to  the  glass,  thereby  greatly  expediting  the 
process. 

To  form  a  plaited  filter,  take  a  square  of  good  porous 
paper  and  fold  it  diagonally,  as  in  Figure  6.  Turn  A  upon 
B  to  obtain  the  crease  E,  and  open  it;  then  double  A  upon 
E  in  the  same  direction  to  make  crease  G;  and  holding 
this  plait  between  the  fingers,  make  the  fold  between  P  and 
D  divide  the  space  between  E  B  and  B  D  in  the  same 
manner. 

Figure  7  shows  the  position  of  the  filter  in  the  funnel. 
After  the  filter  has  been  properly  secured  in  the  funnel, 


REDUCTION  OF  WASTE  RESIDUES. 


441 


and  previous  to  the  addition  of  a  liquid  containing  a  pre- 
cipitate, the  filter  should  be  thoroughly  wet  with  some  clean 
water,  as  by  these  means  the  pores  of  the  paper  are  opened, 
rendering  the  filter  less  liable  to  clog  than  if  the  turbid 
liquid  were  added  immediately.  There  are,  however,  some 
precipitates,  like  the  chloride  and  sulphide  of  silver,  which, 
so  completely  clog  certain  kinds  of  paper,  as  to  prevent  the 
slightest  passage  of  water.  In  such  cases  a  bag  of  felt  must 
be  made  use  of. 

A  very  convenient  filter  for  chloride  of  silver,  when  large 
quantities  are  operated  upon,  is  an  old  felt  hat,  suspended 
from  four  corners  by  means  of  strings,  which  should  be 
fastened  to  the  ceiling  above  the  ^ 


sink.  When  paper  is  used  for  fil- 
tering  liquids  which  pass 
through  very  slowly,  a  series  of 
small  funnels  with  plaited  filters 
should  be  made  use  of.  Large 
funnels  are  objectionable,  as  the 
filters  are  very  liable  to  tear  from 
the  weight  of  the  liquid  having 
no  proper  support  at  the  bottom ; 
but  this  trouble  may,  in  a  meas- 
ure, be  remedied  by  placing  a 
piece  of  cotton  loosely  in  the  bar- 
rel of  the  funnel,  so  that  it  reaches 
to  the  paper,  and  it  will  now  act 
as  a  support  for  the  filter.  Loose 
plugs  of  cotton  alone  are  very 
useful. 

When  a  corrosive  liquid  is  to 


be  filtered,  as  a  strong  acid  or  alkali,  a  plug  of  asbestos, 
placed  loosely  in  the  barrel  of  the  funnel,  is  the  only  suit- 
able medium. 

Decantation  has  the  same  object  as  filtration,  namely, 
the  separation  of  water  from  a  precipitate.  It  is  only  re- 
sorted to  when  the  sediment  is  very  heavy  and  subsides 
readily  to  the  bottom  of  the  vessel  without  being  easily 
agitated,  as  for  instance  the  chloride  of  silver.  It  consists 
simply  in  inclining  the  vessel  gently  to  let  the  supernatant 
fluid  run  off,  or  in  draining  it  off  with  a  syphon.  The  sy- 
phon is  a  very  convenient  little  instrument  and  should  al- 
ways be  kept  at  hand. 

The  most  simple  form  of  a  syphon  is  a  small  glass  tube, 
bent  so  that  it  has  two  arms  of  unequal  length.  (Figure  8.) 


442 


REDUCTION  OF  WASTE  RESIDUES. 


The  long  arm  may  be  twenty  inches  in  length,  the  shorter 
one  about  fifteen  inches.  The  syphon  is  filled  with  water, 
the  mouth  of  the  longer  arm  closed  with  a  finger,  and  the 
shorter  branch  introduced,  mouth  downward,  into  the 
liquid  to  be  decanted,  until  it  nearly  reaches  the  level  of 
the  precipitate  without  disturbing  it.  "Upon  removing  the 
Fig.  8.  finger  the  liquid  runs  out  in  a  continu- 

ous stream  and  may  be  almost  wholly 
drawn  off.  If  the  liquid  is  not  injuri- 
ous or  unpleasant  to  the  taste,  the  sy- 
phon may  be  inserted  into  the  liquid 
without  previous  filling,  being  drawn 
over  by  suction  with  the  mouth  through 
the  lower  end. 

A  small  piece  of  rubber  gas-tube 
makes  an  excellent  syphon  It  should 
be  filled  with  water  and  placed  into 
the  liquid  in  such  a  manner  that  the 
end  hanging  over  the  side  of  the  vessel 
is  considerably  longer  than  that  in  the 
liquid.  All  precipitates  should  have 
the  superfluous  water  decanted  off  be- 
fore they  are  thrown  upon  the  filter,  as 
much  time  is  saved  thereby. 

For  more  complete  and  exhaustive  details  of  the  various 
manipulations  for  reducing  Photographic  Wastes  and  Res- 
idues, the  reader  is  referred  to  the  illustrated  work  entitled 
the  Reducer's  Manual,  by  Victor  G.  Bloede,  to  which  book 
we  are  indebted  for  some  valuable  extracts. 


CHAPTER  XLVIIL 


THE  SOLAR  CAMERA  AND  SOLAR  ENLARGEMENTS. 

The  solar  camera  is  in  reality  a  copying  camera,  with  the 
simple  addition  of  a  lens  or  other  attachment,  by  means 
of  which  the  sunlight  can  be  condensed  upon  the  negative, 
and  thus  made  more  powerful.  There  are  two  distinct 
kinds  of  solar  cameras :  one  is  fixed  in  its  place  and  the 
sun,  by  means  of  a  reflector,  is  made  to  shine  along  the 
axis  in  whatever  part  of  the  heavens  this  orb  may  happen 
to  be;  the  other  is  suspended  on  two  axes,  a  vertical  and 
a  horizontal,  and  is  thus  capable  of  moving  in  any  direction 
whatever,  and  consequently  of  following  the  sun's  motion, 

Fig.  1. 


both  in  altitude  and  azimuth.  All  solar  cameras  of  the 
first  class  are  exact  imitations  of  the  well-known  solar  mi- 
croscope. Woodward's  solar  camera  was  the  first  in  date, 
and,  wonderful  enough,  it  is  protected  with  a  patent!  al- 
though the  special  function  of  the  solar  microscope,  previ- 
ous to  this  patent  grant,  was  to  produce  a  picture,  on  a 
screen  behind  the  lens,  of  another  picture  or  object  placed 
in  the  conjugate  focus  in  front.  Some  improvements,  in 
the  way  of  directing  the  reflector  horizontally  and  verti- 
cally, have  since  been  made  in  this  camera;  for  instance, 
in  Gale's  improved  camera  (Figure  1). 


444         THE  SOLAR  CAMERA  AND  SOLAR  ENLARGEMENTS. 

The  diagram  (Figure  2)  shows — A  the  mirror;  B  the 
condensing  lens;  C  the  negative;  D  the  camera-tube  and 
lens;  E  a  rod  for  adjusting  the  negative;  F  a  set  screw; 
the  lines  G  G  and  H  H  represent  the  cone  of  light  thrown 
by  the  condensing  lens.  The  cost  of  this  solar  camera  is 
about  one  hundred  dollars,  including  patent  mirror  and 
condensing  lens,  and  is  now  made  by  the  Willard  Manu- 
facturing Co. 

Some  solar  cameras  have  attached  to  them  an  arrange- 
ment of  clockwork,  called  a  Heliostat,  which  regulates  the 
motion  of  the  reflector  according  to  the  motion  of  the  sun, 
and  thus  keeps  the  sun's  rays  always  parallel  with  the  axis 

Fig.  2. 


of  the  instrument.  This  attachment  makes  this  sort  of 
solar  camera,  in  one  sense  of  the  word,  perfect.  Such  a 
camera  is  fixed  in  a  window  facing  the  south.  This  window 
is  boarded  up,  so  that  no  light  can  enter  the  room,  except- 
ing through  the  lens.  This  room  becomes  the  dark  cham- 
ber— the  camera  obscura.  The  screen  which  receives  the 
image  is  movable  upon  the  floor  behind,  so  that  it  can  be 
brought  nearer  to  the  lens  or  well  drawn  from  it,  accord- 
ing to  the  size  of  the  picture  required.  This  is  a  conveni- 
ent property  of  this  sort  of  camera,  an  advantage  which 
cameras  of  the  second  class  do  not  possess  to  the  same  ex- 
tent. The  general  construction  of  Gale's  solar  camera,  and 
of  all  its  congeners,  is  as  follows : 

First  comes  a  rectangular  reflector  placed  outside  the 
Avindow,  and  capable  of  moving  vertically  and  horizontally, 
and  of  thus  reflecting  the  sun's  rays  perpendicularly  upon 
a  condensing  lens,  which  is  generally  a  plano-convex  lens, 
the  convex  surface  receiving  the  rays.  The  negative  comes 
next  in  order.  It  is  inverted  and  the  film  looks  toward  the 
portrait  lens,  and  is  capable  of  motion  to  and  from  this 


THE  SOLAR  CAMERA  AND  SOLAR  ENLARGEMENTS.  445 

lens  by  means  of  a  horizontal  slide.  The  portrait  lens  or 
distributing  lens  comes  next.  It  is  fixed  upon  a  frame 
which  slides  horizontally;  the  axis  of  this  instrument  is  a 
line  which  passes  through  the  center  of  the  condensing 
lens  of  the  picture  and  of  the  portrait  lens,  which  latter  is 
placed  at  such  a  distance  from  the  condensing  lens  as  to 
allow  the  cone  of  condensed  light  to  come  to  a  focus  in  the 
optical  center  of  the  combination,  or  at  least  in  such  a  po- 
sition that  the  conjugate  cone  of  light,  and  that  of  the  pic- 
ture itself,  shall  occupy  as  nearly  as  possible  the  same  posi- 
tion and  be  of  the  same  size  on  the  screen.  To  produce 
this  result  satisfactorily,  requires  a  certain  ratio  to  exist 
between  the  power 
of  the  condensing 
lens  and  that  of  the 
distributing  lens. 
This  subject  has  not 
met  with  the  study 
which  it  deserves  ; 
and  to  the  want  of 
accurate  knowledge 
in  this  respect,  may 
be  attributed  the 
general  failure  of  or- 
dinary operators.  If 
the  cone  of  the  con- 
densed light,  and  if 
the  cone  of  the  pic- 
ture do  not  coincide, 
it  is  impossible  to 
obtain  a  picture  to- 
tally free  from  what 
is  denominated  the 
ghost,  which  is  a  cir- 
cle of  greater  actinic  force  in  the  center  than  on  the  peri- 
phery of  the  illuminated  disc,  unless  the  former  cone  be 
thrown  entirely  out  of  axis.  Another  cause  that  tends  to 
produce  this  ghost,  is  to  be  traced  to  the  spherical  and 
chromatic  aberration  of  the  condensing  lens.  In  some 
instruments  this  condenser  is  partially  corrected  by  the 
interposition  of  a  concave,  or  a  concavo-convex  lens,  just 
before  the  light  reaches  the  negative.  This  second  or  cor- 
recting lens,  converts  the  converging  ra}rs  of  light  into  a 
parallel  beam  of  light,  which  simply  illuminates  the  nega- 
tive with  a  highly  condensed  and  nearly  uniform  light;  and 


Fig.  3. 


446         THE  SOLAR  CAMERA  AND  SOLAR  ENLARGEMENTS. 


then,  of  course,  the  two  cases,  of  which  we  have  just  above 
spoken,  must  of  necessity  coincide.  By  such  an  arrange- 
ment the  best  work  may  be  expected.  Dr.  Van  Monck- 
hoven's  instruments  are  arranged  somewhat  in  this  man- 
ner; and  the  results  are  well  known  and  are  recommenda- 
tions of  the  cameras.  The  screen  which  corresponds  to 
the  ground  glass  in  the  ordinary  camera,  is  placed  vertically 
behind  the  distributing  lens,  and  so  accurately  that  its 
center  coincides  with  the  axis  of  the  instrument,  and  also 
the  distances  of  either  edge,  laterally  or  vertically  to  the 
center  of  the  lens,  are  in  pair  respectively  the  same. 


In  the  portable  solar  camera  the  screen  which  is  intended 
to  hold  the  sensitized  sheet,  has,  but  comparatively  speak- 
ing, a  short  space  to  move  in;  and  consequently  with  this 
instrument  it  is  very  difficult  to  obtain  life-size  figures,  be- 
cause an  instrument  that  would  do  such  work  must,  of  ne- 
cessity, be  very  unwieldy  from  its  size. 

Notwithstanding  the  advantage  of  Shive's  and  Roettger's 
solar  cameras,  yet  their  great  cost  has  been  the  means  of 
contracting  their  sale.  Roettger's  camera  complete,  with 
a  fourteen  inch  lens,  costs  three  hundred  and  fifty  dollars; 


Fig.  4. 


In  the  portable  camera, 
of  which  Shive's  Helio- 
tropic,  Figure  3,  and  Roett- 
ger's Parallactic,  Figures 
4  and  5,  are  examples, 
there  is  no  reflector.  The 
instrument  itself  is  tilted 
by  the  mechanism  peculiar 
to  each  instrument,  so  as  to 
receive  the  direct  rays  of 
the  sun.  This  is  an  ad- 
vantage over  the  preceding 
instrument,  because  there 
is  always  a  considerable 
loss  of  light  after  reflec- 
tion. Another  disadvan- 
tage of  the  Gale  solar  cam- 
era arises  especially  in 
winter,  when  the  sun's  al- 
titude is  small  and  the 
angle  of  incidence  and  of 
reflection  is  very  large :  the 
light  is  thus  made  very 
weak  by  such  reflection. 


THE  SOLAR  CAMERA  AND  SOLAR  ENLARGEMENTS.  447 

and  the  price  of  Shive's  is  even  greater.  These  solar  cam- 
eras are  only  adapted  for  the  operator  in  large  cities,  who 
have  plenty  of  orders  for  enlarged  work.  The  country 
operators  generally  find  it  cheaper  to  send  their  work  to 
parties  in  the  cities,  who  make  a  specialty  of  this  kind  of 
work,  and  do  no  other.  Any  stock  house  in  New  York  will 
receive  and  execute  orders  for  solar  camera  work  in  the 
best  possible  manner. 

For  the  benefit  of  those  who  can  afford  a  solar  camera 
of  their  own,  we  will  give  the  following  directions  for 
using  it : 

The  Negative.  FiS-  5- 

The  solar  camera  nega- 
tive is,  next  to  the  camera 
itself,  an  object  of  the  ut- 
most importance ;  for  if 
this  is  not  endowed  with 
necessary  and  normal  con- 
ditions, all  attempts  at 
perfection  will  fail.  The 
shades  of  the  negative 
must  be  much  thinner, 
much  more  transparent, 
than  those  of  an  ordinary 
negative;  in  fact,  the  rule 
we  formerly  gave  on  the 
subject  remains  valid, 
namely,  "  that  a  page  of 
print  must  be  legible 
through  the  densest  parts 
of  the  negative."  The 
light,  after  concentration  upon  the  negative,"is  not  power- 
ful enough  to  penetrate  parts  that  are  more  dense  than 
those  indicated;  and,  therefore,  great  opacity  is  permis- 
sible only  where  the  paper  is  to  remain  perfectly  white. 

Furthermore,  the  negative  must  be  endowed  with  the 
regular  gradations  of  light  and  shade;  must  contain  the 
requisite  amount  of  detail;  all  the  middle  tones  between 
mere  outline  and  a  fully-shaded  picture.  For  instance, 
take  a  portrait  combination,  a  one-third  or  card  picture 
lens,  stopped  down  to  half  an  inch,  and  take  a  negative  of 
a  burdock  standing  in  the  shade.  "We  will  suppose  you 
gave  an  exposure  of  ten  seconds.    What  is  the  result  ? 

The  result  is  this:  With  all  imaginable  fixing  by  means 


448        THE  SOLAR  CAMERA  AND  SOLAR  ENLARGEMENTS. 

of  intensifiers,  the  negative  is  a  black  and  white  picture — 
a  sketch — a  congeries  of  mere  outlines;  the  shadows  of  the 
depressions  and  undulations  in  the  leaves  are  totally  want- 
ing; even  the  skeleton,  the  branches  and  fibers  on  which 
the  chlorophyl  is  built,  is  invisible.  It  is  true  the  negative 
gives  one  the  conception  of  a  burdock;  but  the  mind  has 
to  fill  up  the  contour.  Such  a  negative  will  produce  only 
a  black  and  white  picture  in  the  solar  camera. 

Try  again;  expose  the  negative  twenty  seconds.  The 
result  is  quite  an  improvement;  there  is  light  and  shade; 
nevertheless,  there  is  something  yet  wanting.  The  medium 
and  lateral  branches  of  the  skeleton  are  all  here,  but  the 
minor  reticulations  and  interlacings,  as  well  as  the  protrud- 
ing fibullse,  are  still  invisible. 

Try  once  more.  Give  an  exposure  of  thirty  seconds. 
This  appears  enormous  to  such  of  you  who  have  been  in 
the  habit  of  taking  views  in  eight  or  ten  seconds;  but  you 
will  find  that  such  an  exposure  is  necessary  to  obtain  what 
we  call  a  perfect  negative  of  the  object  in  question.  Now 
you  distinguish  on  the  negative  all  the  detail  that  the  eye 
can  descry  on  the  object;  the  lights  and  shadows,  too,  are 
in  perfect  relief.  Such  a  negative  is  a  delightful  thing  to 
look  upon;  it  will  bear  the  most  minute  scrutiny.  Com- 
pare it  with  those  you  have  been  in  the  habit  of  taking;  in 
yours  the  leaf  of  the  maple,  the  chestnut  and  the  plane  is 
a  black  blotch,  that  cannot  carry  to  the  mind  what  it 
represents. 

You  know  now  what  we  mean,  when  we  assert  that  the 
negative  must  be  full  of  detail,  of  middle  tone,  of  light  and 
shade  in  regular  gradation.  Such  must  be  the  quality  of 
a  negative  for  the  solar  camera;  and  with  such  a  negative 
you  may  obtain,  by  proper  management,  an  enlarged  pic- 
ture almost,  if  not  quite,  as  good  as  one  taken  by  contact 
printing. 

Now  in  order  to  take  such  a  negative,  you  must  make 
certain  changes  in  your  working  materials.  In  the  first 
place,  dilute  the  collodion  with  a  mixture  of  equal  parts 
of  ether  and  alcohol,  until  it  flows  quite  easily  over  the 
glass  plate  and  leaves  no  lines  on  the  dry  film.  Add  to  it 
also  a  few  drops  of  tincture  of  iodine.  In  the  next  place, 
filter  the  collodion  and  wash  the  collodion  bottle,  the  ori- 
fice and  the  stopper  carefully,  and  rub  off  all  adhering 
pieces  of  collodion.  All  this  is  necessary  to  ensure  success. 

Choose  the  finest  and  clearest  plates  of  glass  for  this  pur- 
pose.   Reject  every  plate  that  contains  a  flaw  of  any  kind. 


THE  SOLAR  CAMERA  AND  SOLAR  ENLARGEMENTS.  449 

Filter  the  silver  solution  as  well  as  the  developer.  Have 
everything  in  good  working  condition. 

Expose  long  enough  to  get  detail.  We  cannot  prescribe 
a  definite  rule  on  this  score ;  you  must  study  it  out  in  con- 
nection with  the  objects  to  be  delineated,  and  the  intensity 
and  direction  of  the  light;  but  expose  long  enough;  over- 
exposure is  better  than  under-exposure;  for  the  former 
can  be  controlled  in  the  development,  but  we  cannot  pro- 
duce by  development  what  light  has  not  instituted  by  its 
physical  impression. 

As  soon  as  the  picture  is  complete  in  light,  shade  and 
detail,  stop  all  further  development;  wash,  fix  and  again 
wash.  Now  examine  the  negative.  If  the  shades  are  too 
thin,  too  transparent,  add  a  drop  or  two  of  the  silver  solu- 
tion to  two  or  three  drachms  of  the  developer,  shake  the 
mixture  and  pour  it  upon  the  negative ;  this  will  soon  pro- 
duce the  requisite  amount  of  intensity;  but  the  probability 
is  that  no  intensification  is  necessary,  and  will  seldom  or 
never  be  necessary.  We  mention  the  expedient  to  be  re- 
sorted to  in  case  of  necessity.  If  there  are  any  specks  or 
flaws  in  the  negative,  it  must  be  taken  over  again;  for 
every  speck  and  flaw  will  be  magnified  in  the  print. 

Get  the  negative  right  to  begin  with,  then  you  have  a 
fair  reason  to  hope  for  success.  Of  course  it  is  supposed 
all  the  time  that  there  is  not  the  slightest  veil  or  tendency 
to  fogging  on  the  negative  film;  this  would  be  a  great  det- 
riment to  its  good  working  qualities,  and  would  cause  it 
to  be  rejected  at  once. 

Dry  the  negative  when  complete;  do  not  varnish  it,  un- 
less your  varnish  is  colorless  and  entirely  free  from  par- 
ticles of  every  description. 

The  Camera. 

When  about  to  print  take  out  the  camera  upon  the  roof 
or  elsewhere,  if  it  is  of  the  portable  kind,  and  place  it  in  a 
position  where  there  will  be  no  need  of  moving  it -from  this 
position,  until  the  printing  operation  is  complete;  place  it, 
too,  where  it  is  not  liable  to  be  jarred  or  agitated  by  the 
wind.  Previous  to  undertaking  any  print,  ysu  must  ex- 
amine the  screen  on  which  the  sensitized  sheet  is  to  be 
pinned  or  tacked,  in  order  to  ascertain  whether  it  is  verti- 
cal to  the  axis  of  the  distributing  lens,  and  parallel  to  the 
board  on  which  the  lens  is  screwed.  You  must  be  very 
particular  about  this  point.    In  order  to  test  this  parallel- 


450         THE  SOLAR  CAMERA  AND  SOLAR  ENLARGEMENTS. 

ism,  we  find  the  center  of  the  screen  and  draw  a  circle  on 
it  and  two  diameters,  one  horizontal  and  the  other  vertical. 
A  circle  is  also  drawn  on  the  board  to  which  the  lens  is 
attached,  concentric  with  the  periphery  of  the  brass  flange, 
and  two  similar  diameters  are  constructed.  If  the  two 
planes  are  parallel,  the  distances  from  the  extremities  of 
the  corresponding  diameters  must  be  all  equal  to  each 
other  See  that  this  is  so  before  you  proceed.  See,  too, 
that  the  screen  can  be  firmly  adjusted  in  its  place. 

Pin  a  sheet  of  white  paper  upon  the  screen,  and  place 
the  negative  in  the  holder.  Now  cause  the  sun  to  shine 
upon  the  condenser,  and  in  the  direction  of  the  line  of  col- 
limation,  or  along  the  axis  that  joins  the  center  of  the  con- 
denser and  the  lens.  Move  the  carriage  containing  the 
negative  backward  and  forward,  until  the  picture  upon  the 
sheet  of  paper  is  sharp  and  clear.  Bind  the  carriage  in 
position,  and  adjust  the  focus  to  the  greatest  accuracy  in 
the  following  manner: 

Provide  yourself  with  a  small  Galilean  telescope,  such  as 
is  used  in  opera  glasses — one  of  the  components  of  an 
opera  glass  is  just  the  thing.  This  is  your  focusing  glass. 
Adjust  it  to  focus  at  a  given  distance  from  the  picture, 
where  you  can  easily  rest  the  telescope  against  some  rigid 
support,  and,  at  the  same  time,  move  the  focusing  screen 
that  moves  the  plateholder.  If  the  negative  is  sharpest  in 
the  middle,  or  on  a  given  part,  focus  upon  this  part,  and 
make  the  picture  upon  the  screen  sharp  in  reference  to  this 
particular  part.  There  is  no  possibility  of  equalizing  the 
focus  here,  by  focusing  half  way  between  the  center  of  the 
picture  and  the  peripheral  parts,  as  we  are  sometimes  wont 
to  do  with  a  landscape;  for  by  doing  so  the  parts  (if  cen- 
tral) that  are  sharp  will  now  not  be  sharp  in  the  picture. 

Focus  upon  the  sharp  parts. 

Bind  or  screw  the  lens,  the  plateholder,  the  condenser, 
and  the  screen  firmly  in  position. 

Furthermore,  ascertain  whether  your  lens  produces  any 
flare  or  ghost.  It  is  very  probable  that  it  will  produce  a 
company  of  these  infernal  genii,  even  although  the  lens 
may  have  no  stop,  which  is  supposed  by  some  persons  to  be 
the  prime  cause  of  the  fraternity.  We  do  not  intend  here 
to  discuss  the  subject  of  their  cause,  but  will  show  them  to 
you.  Let  the  sun's  disc  move  quickly  over  the  surface  of 
the  condenser,  while  at  the  same  time  you  observe  the 
picture  on  the  screen.  You  will  perceive  one,  two,  three, 
etc.,  illuminated  circles  move  across  the  field  of  vision  over 


THE  SOLAR  CAMERA  AND  SOLAR  ENLARGEMENTS.  451 

the  picture — these  are  ghosts.  One — the  principal  one — 
moves  in  a  direction  opposite  to  that  of  the  sun's  motion; 
the  others  cross  the  surface  of  the  picture  in  an  opposite 
direction. 

If  these  ghosts  are  left  to  disport  themselves  on  your 
picture,  they  will  spoil  its  beauty  in  the  same  way  as  a 
herd  of  grasshoppers  devastate  a  country  wherever  they 
prowl.  Exorcise  them,  therefore;  enunciate  the  wizard 
spell;  besprinkle  them  with  holy  water,  or  invite  them  out 
to  a  dinner  party — invite  them  out  of  the  picture. 

As  we  have  just  observed,  by  causing  the  sun's  disc  to 
move  across  the  condenser,  the  ghosts  move  across  the  pic- 
ture; but  as  we  cannot  move  the  sun,  let  us  move  the  con- 
denser to  the  right  or  left  until  the  ghosts  have  been  con- 
ducted just  off  the  face  of  the  picture — this  is  the  position 
of  the  camera  in  reference  to  the  sun,  by  means  of  which 
your  print  will  be  free  from  the  central  flares  or  ghosts. 
Mark  this  position,  and  keep  your  camera  in  it  during  the 
exposure. 

The  Sensitized  Paper. 

The  albumen  paper  is  sensitized  in  the  usual  way  and 
hung  up  to  dry.  As  soon  as  all  excess  of  silver  has  drained 
off  from  the  lowest  corner,  and  the  sheet  is  no  longer  wet 
on  the  surface,  but  simply  imbued  and  expanded  with 
moisture,  place  the  sheet  on  a  large  flat  board  and  pin 
down  the  edges  all  round  firmly  to  the  board,  and  set  it 
aside  to  dry  completely.  While  drying  the  sheet  contracts 
and  becomes  perfectly  flat.  When  dry  the  film  may  be 
formed  just  as  you  are  accustomed  to  operate  in  this 
respect. 

Be  very  careful  that  the  sheet  is  perfectly  dry  before  you 
substitute  it  for  the  focusing  paper.  Pin  it  well  in  place, 
turning  the  portable  camera,  of  course,  away  from  the  sun 
during  the  operation. 

Let  on  the  sun  and  keep  it  in  its  proper  direction  during 
the  whole  exposure.  During  half  the  exposure  the  ghosts 
may  change  place,  thus  equalizing  the  light  on  the  picture. 

If  the  sensitive  sheet  were  not  dry  when  the  sun  was 
turned  on,  the  picture  will  be  nowhere  sharp ;  for,  by  con- 
tracting as  it  dries,  the  paper  gradually  recedes  from  the 
picture  and  makes  the  impression  nowhere  perfect.  Fre- 
quently the  drying  is  irregular,  or  the  pins  give  way  more 
on  one  side  than  on  another,  in  which  case  the  contraction 
is  sudden  in  a  given  direction.  By  this  means  lines,  points, 

21 


452         THE  SOLAR  CAMERA  AND  SOLAR  ENLARGEMENTS. 


leaves,  etc.,  become  doubled.  All  this  sort  of  trouble  is 
very  common,  but  it  can  be  avoided :  Let  the  paper  be  quite 
dry  before  you  begin  to  print 

The  toning  and  fixing  need  no  instruction. 


There  are  several  methods  of  printing  by  development. 
The  following  is  the  one  preferred  by  M.  Libois : 

Take  thin  Saxe  paper  and  float  it  for  a  minute  on  the 
following  salting  solution: 


The  citric  acid  is  first  dissolved  in  two  and  a  half  ounces 
of  water,  and  completely  neutralized  by  bicarbonate  of 
soda,  five  drachms  of  which  are  required  to  neutralize  three 
drachms  of  the  acid.  The  solution  of  citrate  of  soda  thus 
formed,  is  added  to  the  solution  of  the  chloride  of  ammo- 
nium. The  solution  must  have  a  slightly  acid  reaction, 
which  is  attained  by  the  addition  of  a  few  drops  of  citric 
acid  in  solution.  A  small  quantity  of  boiled  arrowroot  is 
also  mixed  with  this  bath,  which  is  said  to  improve  the 
final  tones. 

The  paper  is  then  hung  up  to  try;  after  which  it  is  sen- 
sitized by  floating  it  on  the  following  bath  for  half  a 
minute : 


This  bath  is  acidified  with  a  few  drops  of  a  solution  of 
citric  acid.  The  first  few  drops  produce  a  slight  precipi- 
tate of  citrate  of  silver,  which  is  immediately  dissolved  by 
the  succeeding  drops.  When  this  is  effected  the  bath  is 
sufficiently  acid. 

This  paper  when  dry  is  ready  to  be  tacked  to  the  focus- 
ing screen.  You  expose  until  the  print  assumes  a  lilac 
hue,  which  will  be  a  few  minutes  at  most.  The  image  in 
this  time  will  be  just  visible.  The  paper  is  now  taken  out 
and  immersed  in  the  following  developing  bath : 


Printing  by  Development 


Chloride  of  ammonium, 
Citric  acid, 

Rain  water,    .     ,  .  . 


4  drachms. 
4  " 
25  ounces. 


Nitrate  of  silver, 
Water,  . 


1  drachm. 
18  ounces. 


Gallic  acid, 
Acetate  of  lead, 
Rain  water,  . 


6  grains. 
3  " 
40  ounces. 


To  be  prepared  as  follows: 


THE  SOLAR  CAMERA  AND  SOLAR  ENLARGEMENTS.  453 

Dissolve  a  drachm  of  gallic  acid  in  four  drachms  of  alco- 
hol, and  a  drachm  of  acetate  of  lead  in  twelve  ounces  and 
a  half  of  water.  Take  a  drachm  of  the  alcohol  solution 
and  twelve  drachms  and  a  half  of  the  solution  of  acetate; 
add  these  to  one  hundred  ounces  of  water,  and  then  drop 
in  just  enough  glacial  acetic  acid  to  redissolve  the  slight 
precipitate  of  acetate  of  lead  that  falls. 

A  number  of  prints  may  be  immersed  at  the  same  time 
in  this  bath.  The  development  requires  five  or  six  min- 
utes in  the  dark-room,  and  is  stopped  the  moment  the 
prints  appear  perfect;  over-printing  is  not  needed;  for  the 
fixing  solution  seems  rather  to  improve  the  detail  than  to 
destroy  it. 

"Wash  the  prints  and  then  immerse  them  in  the  follow- 
ing fixing  solution : 

Water,  20  ounces 

Hyposulphite  of  soda,   ....       6  " 

In  this  bath  the  prints  remain  about  four  minutes,  they 
are  then  washed  thoroughly  in  a  running  stream  of  water. 
The  color  of  the  prints,  when  they  leave  the  water,  is  red- 
dish, but  it  assumes  a  beautiful  deep  brown  on  drying. 

Naturally  the  print  may  be  toned  like  any  other  silver 
print.  In  this  case  the  print,  after  development,  is  first 
carefully  washed,  and  then  immersed  in  the  ordinary  gold 
toning  solution,  and  afterward  treated  in  other  respects 
like  any  other  silver  print. 


CHAPTEE  XLIX. 


failures;  their  origin  and  remedies. 

All  photographers  have  been  more  or  less  troubled  with 
imperfections  in  their  negatives,  and  it  is  a  frequent  source 
of  annoyance,  and  we  shall  now  proceed  to  examine  such 
imperfections  and  show  their  nature  and  origin,  and  this 
portion  of  his  experience  is  of  as  much  or  more  value  to 
the  operator  as  any;  for  in  a  process  consisting  of  a  great 
variety  of  manipulations,  on  the  complete  success  of  each 
of  which  the  perfection  of  the  resulting  picture  is  depend- 
ent, it  becomes  of  great  importance  to  possess  the  power 
of  distinctly  referring  any  failures  to  their  exact  origin,  and 
thus  being  enabled  to  apply  the  necessary  cure.  Other- 
wise, the  student  would  have  the  mortification  of  seeing 
plate  after  plate  appear  on  development  with  the  same 
blemishes,  to  which,  having  been  enabled  to  trace  their 
source,  he  would  be  incapable  of  applying  a  remedy. 

It  is  well,  therefore,  to  acquire  the  habit  of  never  pass- 
ing an  imperfection,  and  not  resting  satisfied  until  in  all 
the  various  processes  the  one  causing  it  has  been  discov- 
ered; for  the  following  information  on  this  branch  of  our 
subject  we  are  largely  indebted  to  Mr.  Lake  Price. 

Fogging. 

The  first  defect  we  will  notice  is  of  frequent  recurrence; 
it  is  a  general  obliteration  of  the  forms  of  the  subject  in  an 
opaque  film,  which  prevents  them  from  being  clearly  dis- 
tinguished, in  whatever  direction  they  may  be  viewed. 
This  is  termed  "  fogging,"  and  is  caused  in  a  variety  of 
ways.  It  may  result  from  the  unskillful  use  of  the  devel- 
oper itself;  if  it  is  of  too  great  strength  in  warm  weather, 
when  it  should  have  been  reduced  in  power  by  the  addi- 
tion of  distilled  water  and  acid,  fogging  will  ensue;  or,  at 
a  more  moderate  temperature,  prolonging  the  time  of  de- 


FAILUBES;  THEIR  ORIGIN  AND  REMEDIES.  455 

velopment  beyond  a  certain  limit,  will  cause  the  same 
blemish.  If  weakening  the  solution  in  the  one  case,  and 
shortening  the  development  in  the  other,  does  not  remedy 
the  evil,  the  nitrate  bath  must  be  tested  for  alkalinity  with 
reddened  litmus  or  turmeric  paper.* 

If  its  condition  is  found  satisfactory,  L  e.f  neutral  or  just 
acid,  which  will  be  seen  by  its  allowing  the  reddened  lit- 
mus paper  to  retain  its  color,  the  fault  is  not  there.  If  it 
restores  it  to  its  former  tone  it  is  alkaline,  and  a  drop  or 
two  at  a  time  of  the  dilute  nitric  acid  must  be  added;  test- 
ing between  each  change  with  the  blue  paper,  so  as  not  to 
exceed  the  quantity  necessary,  which  will  be  when  the 
paper  is  tinged  with  red.  Stir  with  a  glass  rod  during  the 
time,  that  the  drops  of  acid  may  be  equally  distributed 
throughout  the  bath  solution,  and  their  action  not  confined 
to  the  mere  surface. 

When  there  is  only  a  very  slight  tendency  to  fog,  it  is 
better  not  to  touch  or  alter  the  bath;  by  using  a  more 
highly  colored  sample  of  collodion  perfect  clearness  of  def- 
inition will  be  restored  to  the  film,  while  at  the  same  time 
every  plate  of  such  quality  of  collodion  that  is  dipped  will 
tend  gradually  to  displace,  more  and  more,  the  small  tend- 
ency to  alkalinity  existing  in  the  bath. 

Indeed,  with  such  a  combination  and  balance  of  proper- 
ties, an  acid  collodion  and  a  neutral  bath,  most  excellent 
qualities  are  produced  in  the  picture;  the  bath,  on  the  one 
hand,  possessing  the  power  to  accelerate  the  action  and 
delineate  the  difficult  colors  or  obscure  radiations  from  the 
subject;  while  its  inclination  to  fog  is  bridled  by  the  acid 
state  of  the  collodion,  which  keeps  the  general  definition 
of  the  plate  and  its  darks  and  half-darks  bright  and  clear. 

Should  the  bath,  when  tested,  be  found  in  good  condi- 
tion, the  fault  maybe  with  the  acetic  acid;  if  it  is  deficient 
in  strength  it  will  not  moderate  sufficiently  the  action  of 
the  pyrogallic  or  iron  in  the  developer:  on  adding  about  a 
sixth  to  one  quarter  more  than  its  original  proportion  to 
the  solution  clear  plates  will  be  obtained;  for  extreme  heat 
use  citric  acid.  When  not  arising  from  these  sources,  fog- 
ging may  be  caused  by  diffused  light  having  acted  upon 
the  film  either  in  the  operating-room,  the  slide,  or  the 

*  Litmus  paper,  when  used  to  test  for  alkalinity,  is  first  reddened.  This  is 
best  done  by  taking  out  the  stopper  of  an  acetic  acid  bottle,  and  holding  a  strip 
of  the  paper  in  the  fumes  inside  ;  it  will  immediately  change  from  blue  to  red. 
Actual  contact  produces  a  less  sensitive  test  paper,  its  texture  being  completely 
saturated  with  the  powerful  acid. 


456 


failures;  their  origin  and  remedies. 


camera,  or  from  the  reflexion  of  light  from  bright  surfaces 
in  the  studio,  or  portions  of  sky  acting  directly  on  the  lens. 
Carelessness  in  the  operator,  viz.,  handling  the  nitrate  bath 
dipper  with  dirty  fingers,  contaminated  by  contact  with 
the  developing  solution  or  fixing  hypo.,  will  creep  down 
the  dipper  into  the  bath  solution;  any  messing  or  allowing 
splashes  of  chemicals  to  fall  into  the  bath,  must  be  avoided 
— it  should  be  kept  rigorously  covered  with  a  loose  cap. 

An  old  bath  has  occasionally  a  tendency  to  fog,  from  the 
accumulation  of  organic  matter  and  presence  of  oxide  and 
nitrate  of  silver;  the  best  remedy  in  this  case  is  to  replace 
it  by  an  entirely  fresh  one. 

Lastly,  and  more  frequently  than  any  of  the  preceding 
causes,  over-exposure  at  large  apertures  of  double  lenses 
is  a  fertile  source  of  this  imperfection,  especially  when  used 
in  the  open  air  and  their  surfaces  carelessly  exposed  to  the 
action  of  diffused  light.  This  especially  applies  to  the  por- 
trait, orthoscopic,  doublet,  and  rapid  rectilinear.  Shade 
the  front  of  the  lens  more  completely.  One  general  line 
of  demarcation  exists  in  fogged  plates,  which  materially 
assists  the  operator  in  discovering  the  origin  of  the  evil;  it 
is  that  when  fogging  proceeds  from  impurity  in  the  chemi- 
cals it  is  on  the  surface,  and  is  removable  by  gentle  friction 
with  the  finger.  If  it  has  been  produced  by  over-exposure 
or  diffused  light  it  is  in  the  body  of  the  film,  as  much  as 
any  portion  of  the  subject  itself,  and  is  incapable  of  re- 
moval. 

Insensitiveness. 

The  next  blemish  we  will  notice,  is  in  the  direct  opposite 
to  the  fogged  appearance  on  the  plate :  it  is  the  insensi- 
tiveness evidenced  by  the  too  great  quantity  of  bare  glass 
seen  on  the  plate ;  this  is  caused  probably  by  acidity  of  the 
bath,  which  must  be  tested  for  it;  if  there,  its  presence  will 
be  denoted  by  the  greater  or  less  degree  of  intensity  of  the 
red  color  which  it  imparts  to  the  litmus  paper,  and  accord- 
ing to  the  proportion^  so  must  the  quantity  of  the  alkali, 
applied  to  rectify  it,  be  regulated.  Some  operators  recom- 
mend ammonia  for  this  purpose ;  the  writer  advises  drops 
of  a  solution  of  carbonate  of  soda,  dissolved  in  distilled 
water,  to  be  used  in  preference,  having  found  it  in  practice 
give  much  better  results.  It  must  be  applied  very  gradu- 
ally, and  the  test-paper  and  stirring-rod  used  as  mentioned 
before. 

If  on  testing  the  bath  its  acidity  is  not  considerable,  and 


failures;  their  origin  and  remedies.  457 

the  operator  has  been  working  it  with  a  rather  highly  col- 
ored collodion,  instead  of  meddling  with  the  bath,  the  bal- 
ance before  mentioned  can  now  be  restored  in  the  contrary 
direction — namely,  by  using  the  most  neutral  sample  of 
collodion  at  hand,  which  will  be  found  as  efficacious  in  re- 
storing sensitiveness,  and  giving  delineation  of  forms  in 
the  bare  portions  of  glass,  as  the  acid  collodion  was  in 
clearing  the  obscured  plate. 

If  the  bath  is  not  in  fault,  the  exposure  in  the  camera 
has  probably  been  of  too  limited  duration,  or  the  diameter 
of  aperture  less  than  the  quality  of  light  would  bear;  in- 
creasing the  time  of  the  first,  or  enlarging  the  other,  will 
entirely  alter  the  character  of  the  succeeding  plate. 

Waviness. 

Eeaminess,  or  wavy  marks,  of  Fig.  1. 

uneven  thickness  in  the  film,  fig. 
1,-  are  most  likely  to  occur  in 
thick  viscous  samples  of  collodion, 
which  are  difficult  to  get  off  the 
glass  with  sufficient  celerity;  in 
hot  weather  all  collodions  will  be 
apt  to  have  this  defect,  owing  to 
rapid  evaporation  of  the  ether  in 
manipulating.* 

This  unevenness  is  most  offensive  in  large  flat  tints, 
backgrounds,  etc.,  with  whose  perfect  appearance  it  of 
course  greatly  interferes,  but  it  is  highly  detrimental  and 
objectionable  in  all  parts  of  a  picture,  for  as  the  thickness 
of  the  collodion  film  is  doubled  in  such  parts,  no  treatment 
which  will  apply  to  them  will  be  successful  for  the  rest, 
and  vice  versa.  If  the  film  be  detained  until  they  are  set, 
the  other  parts  will  be  dry  and  insensitive ;  if  they  are  im- 
mersed when  the  rest  of  the  film  is  ready,  from  not  being 
dry  they  will  be  still  unset,  and  being  soft  the  other  por- 
tions of  the  film  will  drag  them,  and  they  will  be  full  of 
crapey  marks,  which  conditions  occurring  across  features, 
etc.,  are  very  destructive  to  the  picture.  In  warm  weathqr, 
especially,  the  state  of  the  collodion  must  be  carefully 

*  Cadmium-iodized  samples  are  most  apt  to  become  thickened  ;  indeed,  it  is 
probable  that  the  one  cause  of  the  superior  sensitiveness  of  this  class  of  collo- 
dions is  due  to  the  spongey  thickening  or  opening  of  the  structure  of  the  film, 
which  becoming  in  excess  must  be  moderated  as  directed. 


458  failures;  their  origin  and  remedies. 


•watched,  and  as  it  thickens  by  evaporation,  newly  washed 
ether  must  be  added  until  the  necessary  fluidity  is  attained. 

White  Rings. 

Small  white  circles,  as  given  in  fig.  2,  appear  in  the  sub- 
ject.   This  blemish  is  caused  by  the  operator  elevating  the 


Fig.  2. 


mouth  of  the  collodion  bottle  too 
far  from  the  glass  in  laying  the 
film ;  the  action  established  in  the 
liquid,  by  the  minute  bubbles  cre- 
ated, remains  after  they  may  have 
dispersed,  and  their  traces  appear 
in  the  finished  work  in  the  man- 
ner shown.  If  care  is  taken  to 
depress  the  mouth  of  the  bottle 
sufficiently,  before  beginning  to 
pour  the  collodion,  these  marks  will  not  occur. 

Serrated  Marks. 

Peculiar  serrated  marks,  fig.  3,  are  caused  by  a  greasi- 
ness  or  scum  on  the  surface  of  the  bath,  which  attaching 


Fig.  3. 


itself  to  the  film,  slides  down  it 
when  put  to  drain.  This  defect 
disappears  after  dipping  two  or 
threo  plates,  showing  that  they 
have  exhausted  the  impurity  and 
cleansed  the  surface  for  succeed- 
ing ones.  This  blemish  is  entirely 
consequent  on  the  contact  of  gutta 
percha  with  the  bath  solution; 
all  other  precautions  being  taken 
to  avoid  the  presence  of  organic  matter,  dust,  etc.,  it  is  un- 
known in  a  photographic  ware  or  glass  bath. 

Spots. 

Spots,  fig.  4,  are  of  two  kinds; 
those  of  defective  action,  leaving 
bare  glass,  and  printing  black,  are 
caused  in  the  following  manner  : 

Tripoli  and  nitric  acid,  recom- 
mended  sometimes  for  use  in 
cleaning  the  glasses,  adhere  most 
tenaciously  to  their  edges,  and  if 
present  will,  wh6n  the  plate  is 
dipped  in  the  bath,  be  dispersed 


failures;  their  origin  and  remedies.  459 


by  the  solution  though  it  was  intractable  to  water,  and 
settling  on  it,  and  on  succeeding  films,  causes  spots  of  bare 
glass  to  appear.  A  film  that  has  been  kept  too  long  in  a 
new  bath,  or  that  has  been  delayed  before  exposed  in  the 
camera,  will  thus  become  dry,  and  the  collodion  being  acted 
upon  by  the  nitrate  of  silver,  numerous  minute  spots  are 
eaten  into  its  structure. 

The  contrary  appearance — that  is,  spots  of  opacity  on 
the  plate,  printing  white,  fig.  5 — is  produced  by  dust  set- 
tling on  the  film  in  certain  stages  Yig.  5. 
of  adhesiveness  of  the  latter,  and  MaaBMmifTiiintffpflifl^^ 
not  forming  "  Comets,"  but  spots, 

by  minute  centers  of  increased  ac-  ^^^^^^^^^^^P^fef 
tion.   By  the  film  being  laid  from  ^^y^^^^^^^^^^W] 

a  highly  colored  sample  of  collo- 

dion,  and  excited  in  an  old  bath  R^^^^^^^^^^!^?! 

which  has  become  over-iodized; 

lastly,  and  most  frequently,  by  too  B^^^^^^feSrtftl 

prolonged  development  of  an  un-  EBMBBSb^ 

der-exposed  plate,  and  using  excess  of  drops  of  bath  solu- 
tion in  the  developer,  the  effect  of  which  is  to  cover  the 
surface  with  minute  specks  of  concentrated  deposit  of  silver. 

Comets, 

Photographic  "  Comets,"  fig.  6,  are  defects  which  bear  a 
remarkable  resemblance  to  the  forms  of  their  prototypes; 
they  are  caused  by  particles  of  dust  in  the  atmosphere  of 
the  developing-room,  which,  de-  j?\g.  6. 

scending  on  the  wet  film,  reappear  ^^^—^.—m^ 
in  the  picture  in  the  shape  of 
spots,  comets,  etc.,  by  the  action  H||HBS 
for  which  they  serve  as  nuclei;  lilllB^Mr^HB^it^^^ 
when  they  arise  from  this  source,  NHB 
the  tails,  etc.,  stream  from  them  Hun 
in  a  vertical  direction  as  they  lie  DnH 
on  the  surface  of  the  film,  and  are  BB^jji^i^^PsMrlj 
caused   by  action   in   the  bath 

liquid,  retained  by  them,  flowing  downward.  Greater  care 
in  clearing  away  dust,  etc.,  will  prevent  their  being  seen  on 
the  plate.  They  will  likewise  arise  from  an  inferior  quality 
of  collodion;  from  carelessness,  with  a  good  sample,  in  not 
decanting  the  upper  part  of  it  from  a  large  stock  bottle 
into  a  smaller,  tjius  leaving  all  impurities  of  former  manip- 
ulations behind ;  by  using  the  collodion  immediately  after 


460 


failures;  their  origin  and  remedies. 


iodizing;  or  from  not  wiping,  with  sufficient  care,  the  necks 
of  the  bottles  from  dried  fragments  of  collodion  or  dust,  or 
Fig.  7  from  any  flue,  etc.,  off  the  glass- 

cloths,  adhering  to  the  surface  of 
the  plate.  When  they  are  in  the 
collodion  itself  they  may  be  known 
by  the  tail-like  appendages,  etc., 
taking  a  curved  form  of  direction, 
as  in  fig.  7,  consequent  upon  the 
rotary  motion  imparted  to  the 
liquid  in  laying  the  film ;  whereas 
those  dependent  on  the  action  of 
substances  merely  resting  on  the  surface  of  the  film,  have 
direct  vertical  lines  of  drainage  action. 

Straight  lines,  of  varied  intensity,  crossing  the  plate  from 
side  to  side,  are  caused  by  any  pause  of  hesitating  move- 
ment with  which  the  dipping  of  the  film  into  the  nitrate 
bath  may  have  been  accompanied.  As  has  been  mentioned 
the  action  should  be  firm,  prompt  and  consecutive. 


Stains. 

Marks  often  appear  like  small  beards  of  light  following 
the  forms  of  the  high  lights  of  the  subject,  and  streaming 


Fig.  8. 


downward  from  them  in  the  di- 
rection in  which  the  film  stood 
when  exposed  in  the  camera,  as 
shown  in  fig.  8.  This  defect  is 
caused  by  the  plate  not  having 
been  sufficiently  drained  before  ex- 
\  posure ;  the  action  is  caused  thus : 
The  rays  of  light  which  delineated 
the  fingers,  linen,  etc.,  in  the  im- 
age, were  diverged  and  reflected 
by  the  descending  liquid,  and  possessed,  in  the  immediate 


Fig.  9. 


vicinity  of  the  high  lights,  suffi- 
cient power  to  impress  an  action. 
Remedy — to  obtain  a  clearer  out- 
line, drain  the  plate  more  before 
putting  it  into  the  slide. 

The  marks  do  not  attach  them- 
selves to  the  forms  in  the  picture, 
but  are  seen  as  a  parallel  streaki- 
ness  of  various  intensity  and  width 
across  the  picture,  as  in  fig.  9. 


failures;  their  origin  and  remedies.  461 

These  appearances  may  arise  from  three  causes,  and  the 
following  tests  will  enable  the  operator  at  once  to  decide 
to  which  he  should  refer  them.  The  subject  was  taken  in 
the  camera,  of  "  landscape  "  form,  but  the  marks  appear  in 
the  contrary  sense.  The  defect  was  in  the  dark-room;  dif- 
fused light,  some  crevice,  or  insufficient  yellow  blindage, 
were  the  causes — that  is  to  say,  if  they  are  incapable  of  re- 
moval when  the  film  is  gently  rubbed  either  with  cotton 
wool  or  the  finger. 

Marks  similar  in  appearance  to  those  just  described,  but 
appearing  in  the  sense  in  which  the  film  stood  in  the  ni- 
trate bath  are  due  to  alkalinity  or  nitrites,  or  some  impuri- 
ties in  the  nitrate  bath,  and  are  often  met  with  in  an  old 
bath,  in  which  organic  matter  in  one  shape  or  other  is 
present.  They  may  at  once  be  perfectly  distinguished 
from  the  preceding  defects,  which  are  similar  in  appear- 
ance, by  being  entirely  on  the  surface  of  the  film,  and  cap- 
able of  removal  by  friction. 

Another  cause  for  the  appearance  of  such  marks  is  the 
following:  When  working  with  sensitive  conditions  of 
chemicals,  if  with  deficient  quality  of  light,  or  small  area 
of  size  in  the  subject  to  reflect  back  the  pencils  of  light  to 
the  film,  the  operator  should  use  too  small  a  diaphragm  in 
proportion  to  either;  or  that  the  focal  length  in  the  camera 
should  be  considerable — the  darks  of  the  picture  are  not 
thrown  with  sufficient  vigor  on  the  film  to  guarantee  it 
from  the  general  action,  which  partakes  more  of  the  nature 
of  diffused  light  than  of  those  distinct  pencils  of  light — 
with  intervals  of  partial  or  total  privation  of  it — which  a 
more  complete  action  would  possess;  the  consequence  is, 
that  the  lights  are  not  intense,  the  shadows  are  weak,  and 
that  the  drainings  of  the  bath,  liquid  in  their  course  down 
the  film  act  upon  it  lenticularly  in  concentrating  light, 
leave  traces  of  their  passage.  But  if,  on  testing,  the 
defect  arise  from  the  causes  given  above,  the  whole  will 
be  found  in  the  body  of  the  film,  impressed  by  the  ac- 
tion of  light,  and  not  capable  of  removing  by  friction, 
as  some  parts  would  be  if  caused  by  impurities  in  the  ni- 
trate bath. 

Distinct  smears,  with  fainter  deposit  on  them,  are  visible 
across  the  subject.  They  are  probably  caused  by  drops  of 
saliva,  in  blowing  the  surface  of  the  glass,  or  by  perspira- 
tion on  the  hands  of  the  assistant  who  cleaned  them,  hav- 
ing found  its  way  first  to  the  clothes,  and  from  thence  to 
the  surface  of  the  glasses.    The  only  remedy,  in  warm 


462 


failures;  their  origin  and  remedies. 


weather  especially,  is  to  have  a  good  relay  of  white  cotton 
gloves  for  him  to  use. 

Marks  at  the  top  and  corners  of  the  subject,  see  fig.  10 
— which  in  the  camera  was  the  bottom — arise  either  from 
the  film  having  been  too  little  drained,  and  the  accumula- 
tion of  bath  at  the  bottom  during  exposure — or  from  neg- 
lect in  blotting  out  the  slide  between  each  picture.  Both 


study,  the  "collodion  back,"  or  holder,  becomes  sodden 
with  bath  solution,  having  to  work  long  and  much  at  one 
time,  two  or  more  backs  and  inner  frames  will  tell  in  the 
improved  results. 

A  mark  of  greater  light  occurs  along  the  whole  of  the 
bottom  of  the  subject.  The  light  has  got  in  at  the  top  of 
the  slide  while  the  film  was  exposed,  showing  the  necessity 
of  keeping  it  covered  with  a  cloth  while  in  the  camera.  A 
margin  of  insensitiveness,  i.  e.t  bare  glass,  sometimes  above 
half  an  inch  wide,  occurs  all  along  the  top  of  the  subject — 
this  generally  happens  most  when  long  exposures  are  ne- 
cessitated, as  in  interiors,  etc.  The  cause  is  the  accumu- 
lation, at  the  bottom  of  the  film  during  exposure  in  the 
camera,  of  a  band  of  drainage  which  obstructs  the  action 
on  the  film.  Drain  more  closely,  and  connect  the  pieces 
of  blotting-paper  at  the  corners  with  that  behind  the  glass, 
so  as  to  attract,  or  suck  off,  the  super-abundant  moisture. 
The  subject  has  a  vigorous  deposit  on  the  lights,  but  the 
shadows  are  too  much  filmed  over  to  be  bright  and 
telling.  It  cannot  be  over-exposed,  or  the  lights  would 
not  be  so  vigorous ;  it  most  probably,  particularly  if  work- 
ing with  a  double  lens,  arises  from  diffused  light  or  reflec- 
tions. 

It  would  doubtless  be  more  advantageous  that  the  lens 
and  camera  should  be  so  enclosed  that  the  lens,  through 
an  aperture,  should  see  only  the  subject,  thereby  avoiding 
all  reflections  from  surrounding  light  objects  and  giving 
the  purest  definition  of  which  it  is  capable;  but  this,  in 


Fig.  10. 


of  the  above  will  be  aggravated, 
if,  in'  taking  the  slide  from  the 
camera,  it  is  not  carried  in  the 
same  sense  in  which  it  stood,  but 
tilted  or  reversed;  or  if  the  flap, 
after  the  picture  is  taken,  is  too 
violently  closed,  which  has  the 
effect  of  splashing  the  liquid  col- 
lected in  the  groove  upward  over 
the  subject.    As  with  prolonged 


failures;  their  origin  and  remedies. 


463 


practice,  especially  out  of  doors,  is  found  troublesome,  and 
loses  much  time. 

A  much  larger  and  deeper  brass  shade  than  is  usually 
sold  with  each  size  of  lens,  diaphragmed  or  lined  with 
black  cotton  velvet  (a  great  absorbent  of  light)  answers 
every  purpose;  and  has  the  advantage  of  allowing  the 
operator  much  more  freedom  of  action  in  placing  his  cam- 
era, while  the  shade  being  on  the  lens,  follows  its  move- 
ments, when  it  may  be  necessary  to  shift  its  position  in 
the  field,  by  altering  the  sliding  fronts. 

Stains  of  development,  see  fig.  11,  are  in  the  earlier  part 
of  the  photographer's  practice,  very  annoying;  the  most 
frequent  are  those  of  inequality  of  action,  caused  by  un- 
skillfulness  in  not  covering  at  one  sweep  the  whole  of  the 
plate,  or  of  not  keeping  the  de-  j?\g.  11 

veloper  in  continual  motion,  and 
thus  allowing  its  greasy  streaks 
and  stains  to  impress  their  image 
on  the  film.  Using  the  solution 
of  too  great  strength  will  mark 
a  sensitive  film  by  its  sudden  and 
violent  action,  and  the  impossi- 
bility of  evening  it  quickly 
enough;  lastly,  using  too  small 
a  quantity,  in  proportion  to  the  superficies  of  the  film,  is 
sure  to  create  stains  from  its  inefficiency  to  cover  the  ex- 
tent of  surface. 

Patches  of  insensitiveness  arise  in  two  ways,  but  may 
each  be  distinctly  referred  to  its  origin.  The  first  are 
caused  in  the  development,  by  the  operator  having  poured 
the  solution  continuously  on  one  portion  of  the  film,  in- 
stead of  distributing  it  all  over.  The  result  has  been  that 
he  has  washed  away  the  silver,  which  should  have  formed 
the  image,  from  that  part,  and  a  bare  patch  is  seen  in  the 
film;  but  when  arising  from  this  cause  there  is  a  remedy. 
Add  drops  of  bath  to  the  developer,  and  tilting  the  plate, 
apply  it  neatly  to  the  deficient  portion,  in  which  the  sub- 
ject will  immediately  appear,  and  if  done  skillfully,  not  al- 
lowing the  other  parts  to  be  strengthened,  it  will  not  be 
perceived  in  the  finished  picture. 

The  same  sort  of  appearance  results  from  keeping  the 
film  too  long  before  dipping  it  in  the  bath,  especially  in 
hot  weather;  but  there  is  one  appearance  which  at  once 
marks  the  difference  of  the  cause,  namely,  that  when  aris- 
ing from  this  source,  iridescent  tints  accompany  the  mark, 


464 


failures;  their  origin  and  remedies. 


which  in  the  other  were  not  seen,  and  the  application  of 
the  nitrate  drops,  the  effect  of  which  was  instant  in  the 
former,  is  powerless  in  this ;  the  only  remedy  is  in  greater 
pronrptness  with  the  next  film. 

The  defect  caused  by  the  opposite  treatment,  namely, 
dipping  the  film  too  soon,  makes  itself  visible  in  thickened 
edges  of  insensitiveness,  called  "fringes,"  on  the  pouring- 
off  margins  of  the  plate,  and  a  general  rottenness,  reticula- 
tion and  crapeyness  of  the  film,  which  will  probably  tear 
up  with  the  action  of  the  water.  Reticulations,  likewise, 
are  the  effects  of  breathing  over  the  glass,  or  neglecting 
precautions  in  damp  weather;  water  is  thereby  added  to 
the  collodion.  This  is  the  reason  why,  in  inferior  or  un- 
skillfully  prepared  samples  of  collodion,  reticulation  is  a 
frequent  blemish — the  alcohol  and  ether  contain  water,  and 
we  thus  perceive  the  necessity  of  the  caution  given  for  their 
preservation,  in  perfect  order,  in  small  bottles. 

Hypo  stains  are  of  the  most  formidable  and  hopeless  de- 
scription; generally  traversing  the  whole  plate  from  the 
corner  where  a  finger  or  thumb  unwashed,  after  the  devel- 
opment and  fixing  of  the  last  subject,  came  in  contact  with 
the  film — caused  by  messing.  Continual  use  of  clean  water 
and  towel  (no  soap)  is  necessary  in  operating. 

We  have  thus  examined  the  various  causes  of  failure  in 
the  manipulation  of  the  collodion  process,  and  although 
many  precautions  may  have  been  more  dwelt  upon  than 
their  nature  would  apparently  warrant,  such  minute  de- 
tails are  entirely  necessary,  and  if  the  reader  will  only 
strictly  adhere  to  them,  he  need  never  doubt  that  in 
taking  up  a  subject  he  will  be  secure  of  an  unblemished 
negative. 


CHAPTER  L. 


PHOTOMICROGRAPHY  PHOTOGRAPHING    ON  CANVAS — ENAMELING, 

OR  BURNING-IN  PROCESS  PRINTING  ON  IVORY  ENLARGING  BY 

THE  SERUM  OR  WHEY  PROCESS. 

The  following  is  M.  Grirard's  method  of  photographing 
microscopic  objects:  The  application  of  photography  to 
micrography  is  one  of  the  most  useful  accessions  to  the 
natural  sciences,  in  consequence  of  the  exactness  with 
which  the  subjects  are  represented.  If  the  most  conscien- 
tious designer  cannot  depict  with  sufficient  faithfulness  the 
marvelous  organization  of  infinitesimal  objects,  light  pos- 
sesses an  infallibility  in  doing  so. 


Fig.  1.* 


Fie 


Fig.  3. 


Photomicrography  consists  in  the  substitution  of  a  very 
short  focus  for  the  ordinary  objective  lighted  by  reflection; 
it  is  a  kind  of  enlarging  apparatus,  only  very  powerful. 

The  microscope,  inclined  in  the  horizontal  position  with 
the  eye-glass  removed,  has  its  body 
continued  by  an  expanding  cone  up 
to  the  dark  slide.  The  entire  ap- 
paratus is  made  to  rest  on  a  stand 
even  with  the  eye,  mounted  with  the 
greatest  firmness,  so  as  to  prevent  all 
vibration.  This  arrangement  is  much 
more  simple  and  practical  than  using 
one  entire  piece  darkened,  and  at  the 
window  of  which  a  solar  microscope 
is  placed. 


*  A  description  of  the  woodcuts  in  Chapters  L,  LI  and  LII  will  be  found  in 
Chapter  LIII. 


466 


PHOTOMICROGRAPHY. 


The  photographic  processes  used  are  those  ordinarily 
employed  in  practice;  it  is  only  necessary  to  mention  that 
the  development  by  pyrogallic  acid  alone  is  often  prefer- 
able, owing  to  the  uncertainty  there  exists  as  to  the  exact 
intensity  of  the  light.  The  principal  difficulties  are  in  the 
lighting. 


The  focusing  requires  the  greatest  precision,  the  focus 
of  the  objective  being  so  very  short;  it  is  commenced  with 
the  coarse,  and  finished  with  the  fine  adjustment,  and  a 
magnifying  glass  applied  upon  the  ground  glass.  When 
the  length  of  the  apparatus  is  very  great,  it  is  necessary  to 
have  recourse  to  an  assistant,  who  acts  according  to  the 
instruction  of  the  observer. 

On  the  exposure  depends,  in  a  great  measure,  the  value 
of  the  proof.    The  direct  solar  light  can  alone  unite  the 

necessary  photographic  quali- 
ties; the  diffused  light  is  too 
feeble  in  most  cases  to  be  of 
any  utility.  The  artificial  ex- 
posure by  electric  light,  mag- 
nesium, gas,  or  Drummond's 
light  have  only  an  experimental 
interest,  and  are  unsuited  to 
the  usual  exigencies  of  practice. 

It  is  necessary  to  have  a  pure 
and  homogeneous  light,  free 
from  any  inactive  parts,  upon 
the  sensitive  surfaces.  The  so- 
lar rays  generally  come  through  vapors  suspended  in  the 
atmosphere;  they  have  then,  when  reflected,  a  yellowish 
tint  detrimental  to  the  proof.    In  order  to  correct  this 


PHOTOMICROGRAPHY. 


467 


defect,  the  light  should  be  decomposed  by  passing  it 
through  an  agent  which  keeps  back  the  inactive  part  and 
only  allows  the  spectral  rays  to  penetrate,  which  are  the 
most  useful  for  the  impression.  Count  Castracan  was  the 
first  who  employed  a  prism,  which  acts  by  dispersion,  but 
has  the  disadvantage  of  absorbing  a  great  quantity  of  light. 
Mr.  Woodward,  and  afterward  M.  Moitessier,  made  use  of 
a  vessel  faced  with  two  parallel  glasses,  containing  a  solu- 
tion of  sulphate  of  copper  and  ammonia.  This  is  the  most 
advantageous  corrective  employed  for  rendering  light  hom- 
ogeneous, but  it  is  often  with  great  trouble  and  difficulty 
installed  in  its  interposition  on  the  course  of  the  luminous 


Fig.  6. 


rays.  As  a  substitute,  a  very  pure  cobalt-blue  glass  may  be 
used,  which  is  easily  placed  on  the  plate  of  the  microscope. 
Although  it  does  not  possess  the  same  qualities  as  the  so- 
lution of  sulphate  of  copper,  it  is  more  practical.  Such  is 
the  opinion  of  Dr.  Maddox,  who  is  an  incontestable  au- 
thority on  photomicrography. 

For  the  minor  enlargements  the  manipulations  do  not 
present  any  serious  obstacles;  the  lighting  is  easy  and  the 
quantity  of  light  always  suf- 
ficient. But  when  a  power- 
ful objective  is  made  use  of, 
the  front  lens  of  which  is 
not  a  millemetre  in  diam- 
eter, and  on  which  the  lu- 
minous rays,  after  their  rec- 
tification by  the  cobalt  glass, 
are  condensed,  there  is  a 
great  loss  of  intensity,  especially  when  combined  with  a 
length  of  camera  extended  to  two  metres.  It  is  necessary, 
then,  to  condense  the  solar  light  by  means  of  several  con- 
verging lenses  placed  upon  its  course. 


468 


PHOTOMICROGRAPHY. 


The  great  degree  of  enlargement  obtained  is  the  triumph  of 
photomicrography.  For  obtaining  this  with  clearness,  objec- 


Fig  8. 


tives  must  be  employed 
wherein  the  principle 
of  correction  is  most 
carefully  attended  to. 
They  should  be  cor- 
rected beforehand  for 
each  preparation,  on 
account  of  the  varying 
thicknesses  of  the  glass 
covering  used  to  pro- 
tect the  object.  It  is 
by  these  precautions, 
and  the  improvements 
made  by  the  construct- 
ors of  instruments,  that 
we  are  enabled  to  re- 
produce with  clearness 
these  powerfully-mag- 
nified specimens. 

Instead  of  obtaining 
directly  a  great  en- 
largement, a  cliche  may 
be  taken  with  a  weak 
objective  and  enlarged 
by  the  processes  gen- 
erally practiced.  This  method  is  very  attractive,  in  conse- 
quence of  its  success  in  portraits,  but  does  not  succeed  so 
well  with  photomicrography.  The  infinite  minuteness  of 
the  details  requires  no  common  precision,  the  least  imper- 
fections assuming,  in  the  enlargements,  extraordinary  pro- 
portions;  and,  further,  the  difficulty  of  developing  the 

Fig.  9. 


PHOTOGRAPHING  ON  CANVAS. 


469 


cliche  to  be  enlarged  with  the  intensity  desired,  and  the 
complications  which  result  from  the  manipulations,  demand 
special  skill. 

Photographing  on  Canvas. 

The  following  is  Dr.  Loewe's  method  of  obtaining  pho- 
tographs on  textile  fabrics :  I  prepare  linen,  cotton,  silk,  and 
other  similar  material  by  giving  it,  firstly,  a  solution  of 
two  ounces  of  gelatine  dissolved  in  ten  ounces  of  water;  I 
then  treat  it  in  the  manner  hereinafter  described  with  ref- 
erence to  the  canvas.  I  take  canvas  prepared  in  the  ordin- 
ary way  for  photographic  purposes,  that  is  by  using  oxide 
of  zinc  or  lead,  and  I  avoid  the  use  of  iron 
instruments,  and  use  instead  thereof  those 
of  ivory  or  wood  for  spreading  the  coating 
upon  the  canvas;  I  then  add  one  and  a 
half  ounces  of  virgin  wax  dissolved  in  es- 
sence of  lavender  to  one  pint  of  turpen- 
tine. The  canvas  is  prepared  with  three 
coatings  and  dried  spontaneously,  and 
when  dry  I  dissolve  sixty  grains  of  iodine 
of  zinc  in  two  pints  of  distilled  water  and 
with  half  a  potato  and  very  fine  pounded 
pumice  stone;  rub  this  solution  on  the 
canvas,  and  dry  it  with  a  soft  flannel  fill 
the  surface  becomes  brilliant. 

In  carrying  this  invention  into  effect  I  further  use  the 
following  three  solutions :  The  first  for  printing  out  or  de- 
veloping the  object  on  canvas  by  sunlight;  the  second,  for 
enlarging  by  artificial  light;  and  the  third  for  printing  by 
contact  in  a  pressure-frame : 

First  Solution. 

To  the  albumen  of  one  hun-  Fig.  11 

dred  eggs  I  add  ten  pints  of  dis- 
tilled water,  ten  ounces  of  chlo- 
ride of  sodium,  five  ounces  of 
chloride  of  ammonia,  sixty  grains 
tartaric  acid,  one  and  a  half 
ounces  carbonate  of  soda,  two 
ounces  iodine  of  potassium,  one 
ounce  iodine  of  ammonia,  half 
an  ounce  bromide  of  potassium, 
one-quarter  of  an  ounce  bromide  of  ammonia,  one-third  of 


470 


ENAMELING,  OR  BURNING-IN  PROCESS. 


an  ounce  pure  iodine,  twenty  grains  nitric  acid,  one  hun- 
dred and  twenty  grains  chloride  of  gold,  one  pint  of  sul- 
phuric ether  saturated  with  virgin  wax,  beaten  together, 
and  filtered  in  a  funnel  hermetically  sealed.  The  solution 
remains  five  or  six  minutes  on  the  material,  which,  when 
dry,  is  rubbed  over  with  a  soft  flannel  until  a  shining  sur- 
face appears. 

Second  Solution  for  Enlarging  by  Artifical  Light 

I  use  the  same  chemicals  described  in  solution  No.  1,  in 
the  same  proportions,  but  add  three  ounces  chloride  of 
ammonia,  two  ounces  of  magnesium,  one  hundred  and 
twenty  grains  of  pure  iodine,  one  hundred  and  twenty 
grains  iodine  of  lithium,  and  sixty  grains  of  iodine  of 
cadmium. 

Third  Solution  for  Printing  in  a  Pressure- Frame  by  Contact. 

To  two  parts  of  distilled  water  I  add  one  part  of  solution 
No.  1,  and  add  one  hundred  and  fifty  grains  of  chloride  of 
sodium,  and  eight  grains  of  gold  to  each  pint. 

Fig.  12. 


In  addition  to  the  directions  given  on  page  309  for  the 
Enameling  process,  the  following  by  E.  J.  Fowler,  giving 
extracts  from  M.  Camarsac's  new  work  on  the  subject,  will 
be  found  interesting:  The  first  chapter  is  on  the  prepara- 
tion of  the  sensitive  "  collodion,"  which  is  no  collodion  at 
all,  if  we  adhere  to  the  usual  acceptation  of  the  word,  for 
it  is  composed  of — 


Enameling,  or  Burning-in  Process. 


ENAMELING,  OR  BURNING-IN  PROCESS. 


471 


20  grains. 
40  " 

£  ounce. 
10  ounces. 
10  44 

and  in  winter  the  proportion  of  bichromate  of  ammonia 
can  be  increased.  It  is  said  that  the  bichromate  of  ammo- 
nia is  to  be  preferred  to  the  potash  salt,  as  it  gives  more 
intense  pictures,  and  the  "  collodion  "  retains  its  sensitive- 
ness longer.  The  solution  of  gum,  sugar,  and  honey  is 
prepared  in  daylight,  and  the  bichromate  is  added  in  the 
dark.  "When  dissolved,  the  whole  is  filtered  and  kept  from 
the  light.  It  is  very  ne- 
cessary that  this  solution  13* 
be  perfectly  clear,  if  pic- 
tures without  specks  are 
desired,  and  it  should 
not  only  be  well  filtered, 
but  allowed  to  stand  for 
some  days  in  a  tall,  nar- 
row glass  jar,  and  then 
only  the  upper  portions 
used  by  the  photogra- 
pher. The  glass  plates 
must  be  of  the  best  qual- 
ity, and  exceedingly  clean 
and  free  from  dust.  And 
here  let  me  reproduce  a 
hint  from  our  authors, 
which  wrill  be  useful  in 
everyday  work :  Never  rub 
a  glass  plate  clean  just 
before  pouring  on  the 
collodion,  for  the  surface 
is  rendered  highly  elec- 
trical by  the  friction,  and 
attracts  all  the  dusty  par- 
ticles in  its  neighborhood.  It  is  necessary  to  take  trans- 
parent positives  for  enamel  pictures,  and  good  ones  too. 
They  can  be  judged  to  some  extent  by  placing  them  face 
downward  on  a  piece  of  white  paper,  and  noting  if  the 
picture  be  as  full  of  detail  as  required  in  the  enamel. 

There  are  some  important  hints  in  the  chapter  upon  ex- 
posures, based  upon  the  theory  that  the  decomposition 
which  is  effected  in  the  sensitive  film  gives  rise  to  water, 


Honey,  .... 
White  sugar, 
Gum-arabic,     .     .  . 
Bichromate  of  ammonia, 
Water  


472 


ENAMELING,  OR  BURNING-IN  PROCESS. 


and  that  the  glass  of  the  pressure-frame  will  become  dim- 
med with  more  or  less  moisture,  according  to  the  exposure ; 
and  it  is  said  that  a  little  practice  will  enable  operators  to 
judge  of  the  proper  time  from  this  effect.  There  are  sev- 
eral circumstances  which  would  influence  the  regular  pro- 
duction of  this  test  moisture,  and  the  subject  is  practically 
treated  in  the  chapter  I  refer  to. 


Fig.  14. 


The  fourth  chapter  is  devoted  to  the  development  of  the 
image  in  the  dark-room,  and  it  is  recommended  that  the  ex- 
posure be  strictly  timed  rather  than  any  defects  of  exposure 
should  be  left  for  correction  in  the  developing  process. 
The  correction  may  be  made,  but  never  yields  so  good  a 
picture  as  one  which  needs  no  correction. 


ENAMELING,  Oil  BURNING-IN  PROCESS.  473 

For  a  transfer  collodion  for  general  use,  that  made  from 
the  following  formula  will  be  found  serviceable : 

Gun-cotton,  85  grains. 

Alcohol  (.830),  .  5  ounces. 

Ether  (-735^       ...  .     ,     .     5  " 

It  is  recommended  never  to  pour  back  into  the  bottle 
the  excess  of  collodion  from  the  bichromate  picture ;  rather 
waste  it,  for  it  takes  up  a  little  bichromate,  and  thus  pro- 
duces soiled  pictures.  A  collodion  that  will  do  for  trans- 
ferring a  picture  the  size  of  a 
large  brooch  will  be  too  thick  for 
small  pictures  for  rings,  etc.,  so 
that  the  operator  must  use  his 
judgment  in  the  choice  and  pre- 
paration of  his  transfer  collodion. 

The  film  with  the  picture  is 
placed  in  sugared  water,  and  the 
importance  of  this  proceeding  is 
shown  in  subsequent  operations. 
The  collodion  film  must  be  de- 
stroyed, and  sulphuric  acid  is 
the  agent  recommended  for  the 
purpose.  Take  care  and  do  not 
burn  your  fingers  in  performing 
this  operation  ;  if  you  do  you 
will,  perhaps,  not  be  inclined  to 
try  the  acid  again,  so  you  must 
employ  a  longer  method,  which 
consists  in  steeping  the  enamel 
plate  for  twenty-four  hours  at 
least,  with  the  collodion  trans- 
fer upon  it,  in — 

Oil  of  lavender,  100  drachms. 

Oil  of  turpentine,   3  '« 

It  is  often  necessary  to  retouch  the  picture  upon  the 
enamel  before  burning  it  in.  Perhaps  there  are  black 
specks,  etc.,  to  be  got  rid  of.  These  are  removed  under 
tvater  oy  means  of  a  needle  which  is  stuck  in  a  handle;  the 
black  points  are  "  pecked  "  out  carefully,  and  float  to  the 
surface  of  the  water.  If  white  specks  are  the  trouble,  they 
must  be  covered  with  the  same  powder  as  that  of  wrhich 
the  image  is  composed;  and  this  powder  is  ground  up 
with  sugared  water  not  of  the  same  strength  as  that  in 
which  the  picture  was  washed,  but  a  syrup,  for  if  weaker 


474 


ENAMELING,  OR  BURNING-IN  PROCESS. 


it  will  damage  the  image  already  formed.  We  now  are 
ready  for  the  burning-in,  and  can  get  the  enameler's  fur- 
nace ready  after  it  is  lighted  put  in  the  muffle,  and  let  the 
fire  be  well  placed  all  round  it.  When  the  furnace  has  at- 
tained a  cherry-red  heat  the  enamel  can  be  put  in,  and  a 
few  minutes'  burning  is  all  that  is  required.  Here  prac- 
tice is  necessary,  but  it  is  easily  acquired,  and  we  need  not 
spoil  more  than  one  enamel  except  from  inattention. 


Fig.  16. 


After  all  the  care  that  may  have  been  bestowed  upon 
the  enamels  up  to  this  point,  it  may  be  found  that  a  few 
black  points  require  removing  or  white  specks  filling  up. 
The  enamel  powder  is  not  now  ground  up  with  syrup,  but 
with  oil  of  lavender,  and  certain  precautions  are  neces- 
sary, which  are  fully  detailed  in  the  chapter.  Fluoric  acid 
diluted  with  water  is  used  for  taking  away  specks,  etc.,  at 
this  stage,  and  for  softening  down  any  lines  or  shadows 
that  may  be  too  black;  but  avoid  all  these  retouches  as 
much  as  possible  by  great  care  and  attention  in  the  early 
operations.  The  various  enamel  powders  are  referred  to, 
and  it  is  recommended  never  to  use  them  as  found  in  com- 
merce ;  even  those  made  by  the  best  houses  can  be  im- 
proved for  photographic  purposes  by  being  re-ground  in 
small  quantities  on  a  glass  plate,  with  a  glass  muller  and  a 
little  water. 

Fig.  17. 


Here  is  a  plan  for  judging  of  the  quality  of  an  enamel 
powder  for  photographic  operations :  Prepare  a  plate  with 
the  bichromate  solution,  and  develop  the  image  with  fine 
plumbago  powder.  If  the  picture  come  out  well,  the  ex- 
posure and  the  "  collodion  "  are  all  right.    Now  repeat  the 


PRINTING  ON  IVORY 


475 


experiment,  with  the  same  exposure  and  the  same  positive, 
and  develop  with  the  enamel  powder  to  be  tested.  If  the 
result  be  the  same,  well;  if  not,  reject  the  powder  and 
grind  it  again. 

The  finest  black  enameling  powder  is  produced  by  the 
oxide  of  iridium;  but,  as  a  pure  black  is  not  always  desired 
in  an  enamel  photograph,  it  may  be  warmed  by  the  admix- 
ture of  other  colors,  and  the  following  is  given  as  a  recipe 
for  powder  of  this  kind: 

Oxide  of  copper,  2  parts. 

"     cobalt   3  " 

"     iridium,   i-10  part. 

Burnt  sienna,  .  ....         1  44 

Flux,     ...    18  parts. 

As  a  flux,  it  is  recommended  to  grind  up  very  finely  bits 
of  optical  flint  glass,  which  can  be  readily  obtained  from 
any  working  optician  who  grinds  his  own  lenses. 


Fig.  18. 


Printing  on  Ivory.    By  David  Duncan. 


Gollodio- Chloride  Process. 

Very  much  depends  upon  the  ivory  having  a  smooth  or 
polished  surface.  There  are  various  methods  of  obtaining 
this.  A  nice  surface  can  be  obtained  by  rubbing  the  ivory 
with  a  piece  of  wash-leather,  occasionally  dipped  in  putty- 
powder.  When  polished,  immerse  the  ivory  in  a  thin  so- 
lution of  spirit  varnish,  and  dry  gently  over  a  gas  stove  or 
before  the  fire.  Any  kind  of  varnish  will  do  that  is  white 
and  clear.  Then  prepare  the  following: 
22 


476 


PRINTING  ON  IVORY. 


French  gelatine,  1  drachm. 

Water,    1  ounce. 

Loaf  sugar,     .     ......        ^  drachm. 

Coat  one  side  of  the  vanished  ivory  (the  polished  side) 
by  pouring  collodion  fashion,  or  with  a  camel's  hair  brush. 
The  gelatine  solution  should  be  strained  through  fine  mus- 
lin, or  filtered  through  cotton  wool,  until  very  clear.  When 
dry,  coat  with  collodio-chloride  of  silver  in  the  dark-room ; 
dry,  and  print  deep ;  wash,  either  under  the  tap  or  in  a  flat 
dish.  Any  old  toning  bath  will  do  to  tone  the  picture.  Fix 
in  a  weak  solution  of  hypo ;  say — 

Hyposulphite  of  soda,      ....      2£  ounces. 
Water,   20  " 

Very  beautiful  pictures  can  be  obtained  by  the  above. 

Fig.  19. 


U  Ill  ml  i' 

iiiiii!iiiiiiiiiiiiiiiiiiii!iniiiiiiiiiii» 

nil 

iii in  ii  mill  ii 

iiiiii.'^'^MIlii 

iiiiyiiTipipI 

Photo- Diaphanie  Process. 

The  following  is  interesting,  and  the  results  are  beauti- 
ful, but  it  is  difficult  to  manage.  Procure  albumenized  trans- 
fer paper — that  made  expressly  for  photo-diaphanie ;  float 
five  minutes  on — 

Nitrate  of  silver,  120  grains. 

Water,   1  ounce. 

Print  in  the  sun,  if  possible,  and  until  the  high  lights 
are  well  covered.  The  right  amount  of  printing  required 
can  only  be  judged  by  experience.    Wash,  and  tone  in — 

Distilled  water,  10  ounces. 

Pure  chloride  of  gold,    ....        15  grains. 

It  will  take  some  time  to  tone.  "When  toned,  wash,  and 
immerse  the  picture  in  a  saturated  solution  of  hyposul- 
phite of  soda  for  five  minutes.  Now  wash  in  several 
changes  of  water  until  the  albumen  film  upon  which  the 
picture  is  printed  loosens  itself  from  the  paper.  When 
detached,  the  film  floats  on  top  of  the  water  as  a  delicate 
transparency.  The  polished  ivory  is  now  brought  under 
the  film  in  the  water,  and  gently  arranged  by  the  fingers. 


ENLARGING  BY  THE  SERUM  OR  WHEY  PROCESS.  477 


The  picture,  after  coming  from  the  water,  is  placed  be- 
tween smooth  note-paper,  inserted  in  a  book,  and  left 
until  dry. 

Enlarging  by  the  Serum  or  Whey  Process. 

The  following  is  Mr.  A.  J.  Drummond  s  process  for  en- 
larging prints,  as  practiced  by  him  for  some  months  with 
perfect  success:  First  take  sixteen  ounces  of  condensed 
milk,  and  dissolve  in  forty-eight  ounces  of  boiling  water; 
heat  this  solution  to  the  boiling  point,  and  add,  drop  by 
drop,  one  ounce  of  acetic  acid  No.  8,  stirring  gently  all  the 
time. 


Care  should  be  taken  not  to  break  the  curd,  and  wnen 
the  serum  is  formed  decant  in  a  porcelain  dish,  and  allow 
it  to  cool.  Then  filter  it  carefully,  after  which  the  solution 
should  look  bright  and  clear. 

Iodize  by  the  following  formula : 


Dissolve  and  filter  as  before,  after  which  it  is  ready  for 
use.  Brush  over  the  paper,  with  a  wad  of  canton  flannel, 
a  little  of  this  solution,  being  particular  that  every  part  of 
the  surface  is  covered.    Hang  up  to  dry  away  from  dust. 

For  sensitizing,  use  a  solution  of  thirty  grains  of  nitrate 
of  silver  to  one  ounce  of  water;  place  it  in  the  sun  until  it 
becomes  clear,  then  add  a  few  drops  of  acetic  acid  to  pre- 
serve the  lights  of  the  picture. 


Fig.  20. 


Iodide  of  potassium. 
Bromide  of  potassium, 
Serum, 


7  grains. 
5  « 
1  ounce. 


478  ENLARGING  BY  THE  SERUM  OR  WHEY  PROCESS. 

This  also  should  be  spread  upon  the  paper  with  a  wad 
of  canton  flannel. 

For  a  developer  I  use  the  filtered  solution  of — 


Pyrogallic  acid   48  grains. 

Acetic  acid  No.  8,   4  ounces. 

Water,   28  " 

Fixing  Bath. 

Hyposulphite  of  soda,   3  ounces. 

Carbonate  of  ammonia,     ....  ^  ounce. 

Water,  .........  16  ounces. 


Fig.  21. 


From  time  to  time  a  little  carbonate  of  ammonia  should 
be  added,  as  the  bath  is  apt  to  be  too  acid. 

First  focus  the  picture,  sensitize  the  paper,  expose  while 
wet,  as  the  action  on  the  iodide  of  silver  is  much  quicker 
when  in  that  state.  The  pictures  should  be  seen  plainly 
in  the  shadows.  When  printed  and  laid  on  a  piece  of  glass, 
pour  a  little  of  the  developer  upon  the  middle  of  the  paper, 
and  spread  it  quickly  over  the  paper,  either  with  a  glass 
rod  or  a  Avad  of  canton  flannel.  The  picture  then  slowly 
appears,  When  it  is  dark  enough  immerse  it  in  the  fixing 
bath,  and  rub  the  surface  with  the  palm  of  the  hand  to 
clear  the  paper  of  the  developer.  The  picture  does  not 
lose  any  of  its  strength  in  the  bath.  Continue  the  use  of 
the  fixing  bath  until  all  yellowness  of  the  picture  has  dis- 
appeared. 

I  would  also  add  that  a  little  citrate  of  soda  in  solution, 
say  to  the  amount  of  a  few  drops  in  the  sensitizing  solu- 
tion, will  give  the  picture  a  warm  tone;  but,  if  much  be 
added,  the  picture  will  print  more  slowly.  A  very  intense 
negative  can  be  printed  much  quicker  by  using  three 


ENLARGING  BY  THE  SERUM  OR  WHEY  PROCESS.  479 

ounces  of  water  to  one  ounce  of  serum  iodizer;  this  is, 
however,  at  the  expense  of  the  picture.  I  hope  all  who  are 
interested  in  enlarging  by  the  use  of  the  lime  or  electric 
light  will  try  this  simple  process,  and  report  for  the  benefit 
of  non-believers  respecting  the  pictures  developed  by  it. 

The  advantage  I  claim  in  using  condensed  milk  is  that 
it  gives  the  picture  a  richer  tone. 


Fig.  2a 


CHAPTER  LI. 


ON  THE  REPRODUCTION  OF  ENGRAVINGS  AND  LINE  DRAWINGS  IM- 
PROVED DRY  PROCESSES  PROCESS  FOR  OBTAINING  POSITIVES  IN 

COLORS. 

The  following  is  F.  Fink's  method  of  reproducing  en- 
gravings and  line  drawings :  The  publication  of  the  follow- 
ing remarks  on  the  copying  of  engravings  by  means  of 
photography  has  been  decided  upon  by  myself,  less  in  the 
hope  of  making  known  new  data  in  connection  with  such 
a  proceeding,  as  for  the  purpose  of  pointing  out  certain 
reliable  facts  which  may  be  serviceable  to  photographers 
engaged  upon  this  description  of  work.  Those  who  have 
■p.    ^  experimented  at  all  in  this 

direction  know  that  a  col- 
lodion which  gives  excel- 
lent results  in  portraiture 
will  yield  but  a  poor,  weak 
negative  when  used  for  the 
reproduction  of  an  engrav- 
ing or  a  line  drawing.  The 
reason  of  this  is  very  sim- 
ple :  the  iodizing  of  the  col- 
lodion has  been  insufficient 
to  produce  the  necessary 
vigor  required  in  a  picture 
made  up  solely  of  fine  lines. 
To  produce  a  good  negative 
of  this  description  it  is  ne- 
cessary that  a  somewhat 
strongly  iodized  material 
be  used,  as,  for  instance,  a 
collodion  containing  one- 
third  more  of  the  iodizer  than  would  be  required  for  por- 
traiture work ;  such  a  collodion  as  is  condemned  by  the 
portrait  photographer  because  it  is  over-iodized  and  gives 
hard  pictures  is  most  suited  to  the  purpose. 


REPRODUCTION  OF  ENGRAVINGS  AND  LINE  DRAWINGS.  481 


A  negative  of  an  engraving  taken  with  collodion  of  this 
description,  if  sensitized  in  a  slightly  acid  bath  and  ex- 
posed for  a  suitable  period,  should  exhibit  perfectly  clear, 
transparent  lines  on  an  opaque,  inky  black  ground.  The 
exposure  should  be,  if  anything,  rather  too  short  than  too 
long,  for  a  full  exposure,  so  necessary  to  the  production  of 
an  artistic  portrait,  is  fatal  to  the  existence  of  fine 
lines  in  a  negative  of  this  kind.  Over  intensification 
of  the  negative  must  likewise  be  avoided,  as  the  more 
delicate  lines  are  easily  destroyed  by  carrying  this  part  of 
the  process  too  far. 

The  intensifying  solution  I  would  recommend  is  a  devel- 
oper prepared  according  to  either  of  the  following  formulae: 

No.  1. 

Water,                                           .  20  ounces. 

Sulphate  of  iron.    1  ounce. 

Nitrate  of  potash,   J  " 

Alcohol,   2  ounces. 

Sulphuric  acid,  '    .  J  ounce. 

No.  2. 

Water,   10  lbs. 

Citric  acid,   3£  ounces. 

Sulphate  of  iron,   2  " 

Alcohol,   6 

After  the  picture  has  been  completely  developed,  the 
image  is  intensified  by  adding  a  few  drops  of  a  twenty  per 
cent,  solution  of  nitrate  of  silver,  the  treatment  being  car- 
ried on  as  long  as  the  fine  lines  re-  Fig.  25. 
main  visible.  After  fixing,  the  plate 
should  be  well  washed,  and  then  again 
intensified  with  a  concentrated  solu- 
tion of  bichloride  of  mercury,  the 
treatment  with  the  latter  material 
being  repeated  as  often  as  may  be 
thought  necessary — say  from  one  to 
four  times.  With  No.  2  solution  the  subsequent  intensify- 
ing with  bichloride  of  mercury  may  sometimes  be  dis- 
pensed with. 

The  picture  to  be  copied  should,  if  possible,  be  lighted 
from  the  front,  direct  sun  rays  falling  at  an  angle  of  from 
50  to  80  degrees,  yielding  the  best  illumination;  if  the  sun 
is  higher  and  the  rays  fall  at  an  angle  of  10  to  30  degrees, 
shadows  are  cast  by  the  texture  of  the  paper,  and  the 
negative  produced  presents  a  rough,  mealy  appearance, 
which  will  be  found  to  be  in  the  highest  degree  objection- 
able when  an  enlargement  of  the  original  is  prepared. 


482 


IMPROVED  DRY  PROCESSES. 


Improved   Dry  Processes. 

The  Washed-Plate  Process. 

This  is  tlie  simplest  of  all  dry  processes,  and  consists  in 
preparing  and  sensitizing  the  plate  as  for  the  wet  method, 
then  washing  it  well  in  distilled  water,  to  get  rid  of  all 
the  superficial  nitrate  of  silver  solution.  The  plate  is  then 
to  be  carefully  dried  in  the  dark.  The  exposure  should 
not  be  much  more  than  for  a  wet  plate.  Prior  to  de- 
velopment the  plate  must  be  re-immersed  in  the  nitrate 
bath,  and  the  development  conducted  just  the  same  as 
for  a  wet  plate,  the  ordinary  developing  solution  being 
used.  These  plates  will  not  keep.  They  should  be  pre- 
pared over-night,  and  used  the  next  day,  and  developed  in 
as  few  hours  as  possible  after  exposure. 

With  favorable  samples  of  collodion  this  process  yields 
good  pictures. 

TJie  Morphine  Process. 

This  process  was  introduced  by  Mr.  Bartholomew,  and 
has  for  its  merits  considerable  sensitiveness  united  with 
vease  of  preparation.    The  plate  is  prepared  with  the  usual 

bromo-iodized  collodion,  in 
all  respects  the  same  as  for 
the  wet  process.  After  the 
plate  is  sensitized  it  is 
washed  well  with  distilled 
water,  and  solution  of  ace- 
tate of  morphine,  one  grain 
per  ounce,  is  flowed  over 
and  the  plate  allowed  to  dry. 
The  washing  and  flowing 
over  of  the  morphine  may 
be  conveniently  done  by  the 
use  of  dipping  baths.  The 
plates  are  nearly  as  sensitive  as  ordinary  wet  plates.  The 
development  may  be  either  with  iron,  neutral  pyro.,  or  al- 
kaline pyro.  If  iron  be  used,  the  following  developer,  as 
recommended  by  Mr.  G.  "Wharton  Simpson,  may  be  em- 
ployed: 

Double  sulphate  of  iron  and  ammonia,    .   20  grains. 

Sugar  candy,  20 

Water,   1  ounce. 

The  film  after  exposure  must  be  moistened  with  water, 
and  the  above  developer  flowed  over.    In  a  few  minutes  a 


IMPROVED  DRY  PROCESSES. 


483 


well-defined  phantom  image  will  appear.  A  little  acetic 
acid  and  a  drop  of  a  10-grain  solution  of  nitrate  of  silver 
are  then  to  be  added  to  the  developer,  and  the  image  be- 
gins to  gather  strength. 

Additional  acid  and  silver  may  be  added  to  a  fresh  por- 
tion of  the  developing  solution  in  such  proportion  as  the 
appearance  of  the  image  suggests;  the  acid  and  silver  ad- 
ded cautiously  in  case  of  under-exposure,  and  freely  if  the 
detail  is  very  fully  out. 

In  some  persons'  hands  iron  has  not  been  so  successful 
as  a  developer  as  pyrogallic  acid.  In  case  therefore  of 
failure  recourse  may  be  had  to  that  agent. 

It  should  be  mentioned  that  as  these  plates  are  not  to  be 
depended  upon  for  keeping,  they  should  be  used  within  a 
few  days  of  their  preparation. 

The  Coffee  Process. 

This  is  a  simple  but  excellent  dry  process;  its  peculiar- 
ity consisting  only  in  the  preservative  solution  being  a 
sweetened  extract  of  coffee.    The  plate  is  prepared  exactly 

Fig.  27. 


as  for  the  wet  process,  and  after  sensitizing  has  to  be  well 
washed ;  it  is  then  ready  to  be  flowed  over  with  the  follow- 
ing solution,  and  allowed  to  dry: 

Ordinary  ground  coffee,  £  ounce. 

Loaf  sugar,   £  44 

Water,  16  ounces. 

Let  the  water  be  boiling  when  the  coffee  and  sugar  are 
added.  Cool  and  shake  the  vessel.  The  solution  will 
keep  good  for  a  week,  but  must  be  filtered  for  use. 

The  exposure  is  three  times  that  of  wet  plates.  The  de- 
velopment may  be  by  either  neutral  or  alkaline  pyro. 


484  PROCESS  FOR  OBTAINING  POSITIVES  IN  COLORS. 


Process  for  Obtaining  Positives  in  Colors. 

The  following  is  M.  Niepce  de  St.  Victor's  method  for 
obtaining  positives  in  colors : 

Red  Color. 

Prepare  the  paper  with  a  solution  of  nitrate  of  uranium, 
strength  24  grains  to  the  ounce.  Leave  the  paper  from 
fifteen  to  twenty  seconds  upon  this  solution;  then  dry  it 
before  the  fire,  in  the  dark.  Expose  it  in  the  pressure- 
frame  from  eight  to  ten  minutes  in  sunshine,  and  from  one 
to  two  hours  in  the  dark.  Wash  it  for  some  seconds  in 
warm  water  (120°  Fah.),  and  then  immerse  it  in  a  solu- 
tion of  red  prussiate  of  potash,  strength  10  grains  to  the 
ounce.  In  a  few  minutes  the  print  will  acquire  a  beautiful 
blood-red  color.  Wash  it  in  several  changes  of  water,  un- 
til the  water  remains  perfectly  colorless,  and  then  dry  it. 

Fig.  28. 


Green  Color. 


Take  a  red  print  obtained  as  before  described.  Im- 
merse it  for  a  minute  in  a  solution  of  nitrate  of  cobalt. 
Remove  it  without  washing,  and  dry  it  before  a  fire;  it 
will  become  green.  Fix  it  by  putting  it  for  a  few  seconds 
into  a  solution  of  sulphate  of  iron,  20  grains  to  the  ounce, 
and  sulphuric  acid  1  scruple  to  the  ounce.  Wash  it  once 
in  water,  and  dry  it  before  the  fire. 

Violet  Color. 

Prepare  the  paper  with  nitrate  of  uranium,  as  in  the  red 
process.  Expose  it  in  the  pressure-frame;  wash  it  with 
warm  water;  and  develop  the  image  with  chloride  of  gold, 


PROCESS  FOR  OBTAINING  POSITIVES  IN  COLORS.  485 

2  grains  to  the  ounce.  "When  the  print  has  acquired  a  fine 
violet  color  wash  it  in  several  changes  of  water,  and  dry  it. 

Blue  Color. 

Prepare  the  paper  with  a  solution  of  red  prussiate  of 
potash,  100  grains  to  the  ounce;  dry  it  in  the  dark.  Re- 
move the  print  from  the  pressure-frame  when  the  shadows 
have  acquired  a  light  blue  tint.  Immerse  it  for  a  few  sec- 
onds in  a  cold  saturated  solution  of  bichloride  of  mercury, 
wash  it  once  in  water,  and  then  put  it  into  a  solution 
of  oxalic  acid,  saturated  when  cold,  and  heated  to  about 
100°  Fah.    Wash  it  three  or  four  times,  and  dry  it. 


Fig.  29. 


CHAPTEK  LII. 


SEL  CLEMENT  MEZZOTINT  PHOTOGRAPHS  THE  MAGIC  PHOTOGRAPH 

 CABINET  PORTRAITS  GAGE's  IMPROVED  PHOTOGRAPHS. 


A  short  time  ago,  says  the  British  Journal,  we  mentioned 
that  we  had  received  a  specimen  of  a  new  salt,  containing 
silver,  which  is  sought  to  be  introduced  in  England  as  a 
substitute  for  the  ordinary  nitrate  of  silver  which  we  have 
been  so  long  accustomed  to  use.  As  many  were  anxious 
PI    gQ  to  know  the  constitu- 

tion of  this  salt,  we 
submitted  a  sample  to 
analysis,  and  obtained 
the  results  which  we 
shall  now  give.  As 
the  reader  is  probably 
aware,  the  sel  clement 
is  sold  in  small,  broken, 
trans]ucent  cakes  of  a 
slightly  greenish  tinge, 
and  which  are  deliquescent,  and  therefore,  require  to  be 
retained  in  a  well-closed  bottle.  The  cause  of  this  tend- 
ency to  deliquesce  will  be  presently  shown.  The  salt  is 
readily  soluble  in  water  without  the  slightest  turbidity 
being  produced,  and  can  then  be  employed  for  sensitizing 
paper,  etc.,  just  as  in  the  case  of  the  ordinary  silver  salt. 

When  submitted  to  analysis,  the  sel  clement  was  found  to 
be  composed  of — 


Nitrate  of  silver, 
Nitrate  of  magnesia, 
Combined  water, 


31  5  per  cent. 
570  " 

8-5  " 

1000 


It  will  be  seen,  therefore,  that  nitrate  of  silver  consti- 
tutes but  little  more  than  one-third  of  the  salt,  the  nitrate 
of  magnesia  and  its  combined  water  forming  the  bulk  of 
the  sample.    In  using  the  nitrate  of  magnesia  it  is  impos- 


SEL  CLEMENT. 


487 


sible  to  avoid  the  presence  of  a  certain  proportion  of  water, 
as,  when  a  solution  of  the  nitrate  is  evaporated  to  dryness, 
-and  the  last  portions  of  water  are  expelled  by  heat,  the 
salt  decomposes,  and  a  basic  compound  is  left  behind, 
which  yields  but  little  soluble  matter  to  water.  Hence,  if 
the  evaporation  be  carried  so  far  as  to  drive  off  more 
water  than  the  proportion  shown  in  the  above  analysis, 
the  risk  would  be  incurred  of  producing  the  insoluble  com- 
pound above  referred  to. 

The  set  clement  may  be  prepared  in  the  following  way. 
Take  of— 

Silver,   100  parts. 

Magnesia,  calcined,   66  " 

Nitric  acid  (sp.  gr.  1*42)  a  sufficient  quantity. 

Dissolve  the  silver  in  three  times  its  weight  of  the  nitric 
acid  diluted  with  its  own  bulk  of  water;  then  add  the  mag- 
nesia, stirring  well,  and  gradually  pour  in  sufficient  nitric 
acid  to  dissolve  all  the  mag-  Yig.  31. 

nesia  and  leave  the  solution 
but  slightly  acid.  The 
mixed  solution,  which 
should  be  filtered  if  not 
quite  clear,  is  then  to  be 
evaporated  in  a  shallow  dish 
to  a  very  small  bulk,  with 
the  acid  of  the  water  bath, 
to  such  an  extent  that  a 
portion  when  removed  on  a 
glass  rod  immediately  solid- 
ifies on  cooling.  When  suf- 
ficiently  evaporated  the 
whole  may  be  left  aside  until  cold,  taking  the  precaution, 
however,  to  cover  the  capsule  so  as  to  prevent  the  access 
of  moisture;  the  cakes  of  salt  should  then  be  broken  up 
and  preserved  in  a  stoppered  bottle  for  use.  "When  treated 
with  water  the  salt  should  dissolve  completely  without 
leaving  any  residue. 

Any  difficulty  which  exists  in  preparing  the  salt — or 
rather  the  mixture  of  salts — above  mentioned  is  encoun- 
tered during  the  evaporation  of  the  solution,  as  the  incau- 
tious continuance  of  a  high  temperature  for  a  considerable 
time  is  certain  to  interfere  with  the  production  of  a  satis- 
factory sample,  such  as  that  we  have  examined.  Few  will 
care  to  go  to  the  trouble  of  preparing  a  salt  which  can  be 


488 


SEL  CLEMENT. 


now  so  cheaply  procured;  but  those  who  wish  to  test  the 
manifold  virtues  of  this  new  claimant  for  photographic 
favor  will  find  the  above  directions  sufficient  to  enable 
them  to  attain  their  object. 

Now,  as  to  the  value  of  this  set  clement  it  has  been  al- 
ready stated  that  there  are  some  respects  in  which  it  may 
prove  a  useful  substitute  for  a  strong  bath  of  pure  nitrate 


tion,  which  probably  can  then  less  freely  permeate  the  sur- 
face of  the  albumen;  hence  the  tendency  is  to  retain  the 
sensitive  material  more  completely  on  the  surface  of  the 
paper.  It  is  probably  in  this  way  that  the  nitrate  of  pot- 
ash acts  when  added  to  the  nitrate  bath,  as  there  can  be 
no  question  about  the  advantage  resulting  from  its  addi- 
tion to  very  weak  baths;  and  the  new  salt  is,  therefore,  a 
convenient  form  in  which  to  use  the  material  for  a  com- 
pound bath,  and  yet  one  containing  a  minimum  of  silver. 
There  is  another  advantage  arising  from  the  employment 
of  a  neutral  salt  as  an  addition  to  the  printing  bath,  and 
that  is  the  tendency  which  these  bodies  possess  of  pre- 
venting the  albumen,  or  silver  compound  of  albumen,  from 
entering  the  solution. 

Even  apart  from  the  preceding  considerations,  it  is  an 


Fig.  32. 


of  silver.  Its  chief  advan- 
tages probably  depends  on 
the  improved  tone  which  the 
prints  take  when  the  double 
salt  is  used  to  sensitize  the 
paper.  The  difference  in 
price,  as  the  above  analysis 
proves,  is  only  an  apparent 
and  not  a  real  one;  but  the 
chief  point  is  that,  in  employ- 
ing a  bath  of  forty  grains  of 
the  set  clement,  it  is  possible 
to  get  results  in  printing 
similar  to  those  afforded  by 
a  bath  of  nitrate  of  silver  of 
nearly  eighty  grains  in 
strength,  although  the  actual 
amount  of  silver  salt  present 
forms  but  little  more  than 
one-third  of  the  whole. 


The  advantage  appears  to 
arise  chiefly  from  the  in- 
creased density  of  the  solu- 


MEZZOTINT  PHOTOGRAPHS. 


489 


interesting  fact  that  the  presence  of  a  salt  of  magnesia  is 
found  to  exercise  such  a  marked  influence  over  the  tone 
which  the  prints  take  on  immersion  in  the  gold  bath,  and 
adds  an  additional  fact  to  the  long  list  which  we  already 
have  in  proof  of  the  power  which  many  of  these  neutral 
salts — such  as  those  of  baryta,  lime  and  magnesia — un- 
questionably possess  of  influencing  the  deposit,  or  rather 
substitution,  of  metal  in  the  toning  bath. 

Mezzotint  Photographs. 

Mr.  Carl  Meinerth  has  obtained  a  patent  for  "  Mezzo- 
tints "  which  he  describes  as  follows :  This  style  of  picture 
is  the  result  of  a  process  obtained  by  me  after  following 
with  great  interest  the  path  pointed  out  by  Claudet,  Dall- 
meyer  and  other  distinguished  leaders  of  our  fraternity,  with 
the  great  object  in  view  of  equalizing  focal  differences  and 
blending  light  and  shade  in  portraiture. 

I  have  experimented  with  the  various  methods,  but  as 
far  as  my  own  experience  goes,  and  what  I  have  seen  from 
the  results  of  other  co-laborers,  the  necessary  detail  in  the 
parts  of  the  face  is  rather  too  much  "  blurred  "  in  the 
effort,  and  I  would  be  very  glad  to  see  a  specimen  which 
would  convert  me  to  a  different  opinion  and  to  immediate 
public  recantation. 

To  obtain,  then,  this  beautiful  "blurring,"  and  yet  retain 
all  necessary  clearness  in  detail,  was  my  aim  and  end;  and 
so  far  I  have  yet  to  meet  a  photographic  or  other  artist 
who  is  not  struck  with  admiration  at  the  roundness  and 
softness  of  my  result,  and  the  absence  of  all  harsh  shadows. 

There  are  some  artists  among  us  who  prefer  taking  and 
showing  the  wart  on  a  nose,  not  only  so  but  also  the  hairs 
growing  on  it !  To  such  "there  is  no  heaven  of  art,"  how- 
ever; they  had  better  remain  on  terra  firma  and  focus  on 
hairs,  and  even  split  them ! 

It  is  true  the  shadows  spoken  of  can  be  artificially  re- 
moved by  retouching  the  negative  or  the  print;  but  this  is, 
of  course,  an  artificial  effort  readily  perceived,  and  con- 
nected with  additional  labor  and  expense.  Moreover,  it  is 
natural  to  infer  that  even  the  best  photographs,  produced 
without  any  such  retouching,  will  and  must  greatly  improve 
by  my  method  of  printing,  and  still  remain  to  be  a  purely 
photographic  production,  leading  our  art  on  steps  higher 
toward  the  realm  of  all  art. 

Now,  as  to  my  method:  I  first  conceived  the  idea  last 


490 


THE  MAGIC  PHOTOGRAPH. 


winter  that  the  desired  diffusion  of  light  might  be  obtained 
between  the  negative  and  the  paper.  My  first  experiments 
were  made  by  inverting  the  negative  itself.  The  diffusion, 
however,  was  too  great  as  many  a  printer  may  have  seen, 
who  threw  away  the  print  after  having  accidently  placed 
the  negative  upside-down,  except  when  the  negative  glass 
was  very  thin.  The  image,  however,  was  produced  re- 
versed, like  an  ambrotype  or  positive,  and  very  thin  nega- 
tives are  not  desirable  on  account  of  their  liability  to  break. 
The  result,  however,  was  very  promising.  It  led  me  natu- 
rally to  substituting  a  thin  layer  of  mica,  of  glass,  or  a  mat, 
simply  to  introduce  a  very  short  transparent  space  be- 
tween the  negative  film  and  the  material  to  print  upon, 
whether  the  glass  of  the  negative  itself  or  another  trans- 
lucent medium.  This  is  the  specification  of  my  idea,  which 
I  now  have  perfected  and  put  into  practical  use,  and  for 
which  United  States  Letters  Patent  was  granted  to  me. 

The  intelligent  photographer  will,  of  course,  understand 
that  while  this  new  principle  of  using  the  light  in  printing 
requires  no  change  whatever  in  the  common  process  of 
silver  printing,  it  is  as  necessary  to  have  a  good  negative 
for  this  as  for  any  other  process,  in  order  to  insure  the 
best  results. 

Besides  the  beauty  of  the  effect,  there  is  another  benefit 
derived  from  this  simplest  of  all  processes,  every  picture 
flatters  !  Since  I  have  made  the  first  mezzotintoes,  I  had 
scarcely  any  others  ordered.  Freckled  faces,  high  cheeks, 
sunken  eyes,  all  are  delighted  with  their  pictures.  Those 
ugly  defects  are  so  much  subdued,  if  not  entirely  removed, 
and  all  this  simply  by  the  printing.  And  you  will  find  that 
no  other  but  this  method  will  do  this  so  effectually  with- 
out any  artificial  means,  without  detriment  to  the  likeness 
and  the  pristine  purity  of  the  photograph. 

The  Magic  Photograph. 

Some  time  since  much  interest  was  excited  by  the  above 
novelty,  and  we  think  that  a  formula  for  making  it  should 
have  a  place  in  this  work. 

Take  in  the  first  place  an  ordinary  print,  a  card  picture 
for  instance,  on  albumen  paper,  beneath  the  negative  in  the 
usual  way,  and  when  sufficiently  printed  let  it  be  carefully 
washed  in  the  dark-room,  so  as  to  remove  all  the  free  nitrate 
of  silver,  etc.  Now  immerse  it  in  the  following  solution, 
also  in  the  dark-room: 


THE  MAGIC  PHOTOGRAPH. 


491 


Saturated  solution  of  bichloride  of  mercury 

(corrosive  sublimate),  1  ounce. 

Hydrochloric  acid,  1  drachm. 

The  saturated  solution  is  previously  prepared  by  putting 
into  water  more  bichloride  of  mercury  than  it  will  dissolve 
by  shaking  in  about  twelve  hours.  Pour  off  the  quantity 
required. 

The  print  will  gradually  be  bleached  in  this  liquid,  in 
the  ordinary  meaning  of  the  word,  that  is,  it  will  disap- 
pear; but  the  fact  is,  the  print  is  still  there,  its  color  alone 
is  changed,  a  double  salt  having  been  formed  of  mercury 
and  silver  which  is  white,  as  many  of  our  readers  who  have 
been  in  the  habit  of  intensifying  with  a  mercurial  salt  are 
aware  of.  As  soon  as  the  print  has  quite  disappeared,  the 
paper  is  thoroughly  washed  and  dried  in  the  dark-room; 
it  is  also  preserved  between  folds  of  orange-colored  paper, 
in  order  to  keep  it  from  the  action  of  light,  for  the  surface 
is  still  in  some  measure  sensitive  to  light. 

The  bleaching  of  the  print,  that  is,  its  conversion  into  a 
white  salt,  is  effected  more  quickly  by  keeping  it  in  motion 
in  the  mercurial  solution. 

As  we  have  said  before,  the  print  has  not  been  bleached 
in  reality;  the  substance  which  originally  formed  it  is  still 
there,  together  with  a  new  substance,  a  salt  of  mercury. 
But  the  two  salts  of  silver  and  mercury  may  be  easily 
brought  out  and  made  visible  by  several  solutions,  such  as 
sulphide  of  ammonium  and  a  solution  of  hydrosulphuric 
acid;  in  fact,  any  of  the  double  sulphides,  ammonia  and 
hyposulphite  of  soda;  the  latter  salt  is  used  in  preference 
to  the  others.  Small  pieces  of  blotting-paper,  therefore, 
of  the  same  size  of  the  prints,  are  cut  out  and  steeped  in  a 
saturated  solution  of  hyposulphite  of  soda  and  then  dried. 

The  magic  photographs  are  packed,  as  before  stated,  be- 
tween folds  of  orange-colored  paper.  The  papers  dipped 
in  hyposulphite  of  soda  are  the  developers,  and  may  be 
packed  between  two  sheets  of  common  writing-paper.  The 
development  is  effected  in  the  following  manner: 

Place  the  albumen  paper  which  contains  the  whitened 
print  on  a  pane  of  glass,  print  side  upward;  on  this  lay  the 
dry  piece  of  blotting-paper  that  has  been  previously  dipped 
in  hyposulphite  of  soda;  moisten  the  latter  thoroughly; 
then  place  over  it  a  pane  of  glass,  and  upon  this  a  weight 
to  bring  the  two  pieces  of  paper  into  intimate  contact.  In 
a  very  short  time  the  picture  will  appear  in  all  its  original 
detail  and  of  a  sepia  tone. 


492     CABINET  PORTRAITS  GAGE'S  IMPROVED  PHOTOGRAPHS. 


Cabinet  Portraits. 


The  success  of  the  carte  de  visite  has  induced  enterpris- 
ing photographers  to  extend  the  idea;  hence  the  "Cabinet" 
portraits.  These  may,  in  one  sense,  be  considered  as  cartes 
of  a  large  growth,  but  the  size  is  improved  in  its  propor- 
tions. The  same  treatment  should  be  used  in  producing 
these  pictures  as  in  cartes;  that  is,  as  full-lengths,  vignet- 
tes, etc.,  and  with  the  usual  accessories  characteristic  of 
indoor  or  outdoor  scenery.  A  different  lens  will  be  neces- 
sary, as  those  used  for  the  cartes  are  too  short  in  focus.  A 
half  or  whole-plate  lens,  or  one  made  expressly,  will  answer 
best. 

The  adopted  size  of  the  cabinet  portraits  is  as  follows: 


There  can  be  but  little  doubt  that,  by  united  action,  this 
size  may  become  a  standard  one,  especially  as  albums  are 
constructed  expressly  for  it.  This  new  size,  among  its 
many  'advantages,  is  well  suited  for  portrait  groups,  in- 
teriors, landscapes,  and  many  other  subjects  for  which  the 
dimension  and  proportion  of  the  carte  are  quite  unfitted. 
It  will  also  afford  a  worthy  opportunity  for  skillful  photo- 
graphers to  break  away  from  the  little  and  petite  effects 
that  are  of  necessity  peculiar  to  the  carte  size,  and  may 
lead  the  public  to  appreciate  and  desire  larger  pictures 
and  better  work,  thus  improving  the  art  in  every  way. 


Mr.  Gage  takes  a  photographic  impression  in  the  usual 
manner,  and  then  places  some  plain,  dark,  dead  surface  in 
front  of  the  camera,  the  sensitive  surface  still  remaining  in 
the  camera.  He  then  removes  the  covering  from  the  lens 
tube,  and  exposes  the  sensitive  surface  on  which  the  im- 
pression has  been  formed  to  the  light  reflected  from  the 
dark  surface,  while  the  dark  surface  is  kept  in  gentle  mo- 
tion, so  as  to  prevent  the  sensitive  surface  from  taking  an 
impression  of  any  wrinkles  or  other  variations  on  the  sur- 
face from  which  the  light  is  reflected.  The  time  of  this 
exposure  is  varied  according  to  the  amount  of  light  re- 
flected and  the  effect  it  is  desirable  to  produce.  The  usual 
amount  of  time  occupied  in  this  exposure  will  be  from  one- 
fourth  to  double  the  time  employed  in  taking  the  invisible 


Size  of  mounted  picture,  . 
Mounting  card,   .  . 
Opening  in  album, 


5|  by  4. 
5*  "  3  7-8. 


Gage's  Improved  Photographs. 


gage's  improved  photographs.  493 

impression;  but  in  some  cases  it  can  be  extended  much 
beyond  this  time.  For  a  dark,  dead  surface  Mr.  Gage 
usually  uses  a  piece  of  thick  black  woolen  cloth  about 
eighteen  inches  square,  attached  by  one  edge  to  a  stick 
about  two  feet  long,  which  is  held  horizontally  and  gently 
moved  in  front  of  the  camera  with  the  left  hand,  while  the 
lens  tube  is  uncovered  with  the  right  hand.  It  is  not  ab- 
solutely essential  that  this  dark  surface  be  kept  in  motion, 
but  it  is  safer.  This  exposure  of  the  sensitive  surface  to 
the  light  reflected  from  a  dark,  dead  surface  apparently 
leaves  the  lightest  portions  of  the  impression  but  little 
changed,  while  it  effects  a  much  greater  change  in  the 
darkest  portions  of  the  same,  and  thus  harmonizes  and 
properly  blends  the  two,  giving  to  the  whole  an  atmos- 
pheric effect  never  before  realized  in  photographic  impres- 
sions; it  also  renders  it  less  difficult  to  obtain  the  neces- 
sary intensity  in  negatives. 


CHAPTER  LIH. 


newton's  dry  processes — description  of  apparatus,  as  illus- 
trated WITH  WOODCUTS,  IN  THE  THREE  PRECEDING  CHAPTERS. 

We  give  here  two  entirely  new  Dry  Processes  discovered 
by  Mr.  H.  J.  Newton,  and  now  published  for  the  first  time, 
the  results  of  which,  as  exhibited  to  us,  are  far  more  beau- 
tiful than  those  of  any  wet  or  dry  process  with  which  we 
are  acquainted. 

The  Tea  Process. 

Take  a  large  tablespoonful  of  Japanese  tea,  put  it  into  a 
bowl  and  add  about  eight  ounces  of  boiling  water;  cover 
it  over  and  keep  it  hot  for  about  an  hour;  then  pour  the 
liquor  off  from  the  leaves,  and  add  sufficient  water  to  make 
the  whole  measure  ten  ounces.  "While  the  tea  is  still  warm 
add  one-half  ounce  of  finely  pulverized  sugar  of  milk;  when 
it  is  all  dissolved  filter  and  it  is  then  ready  for  use.  In 
this  condition  it  will  keep  for  several  weeks.  Sensitize 
your  plates  in  any  bath  which  will  make  clean  negatives  by 
the  wet  processes.  The  best  collodion  for  dry  plates  is 
that  which  works  the  most  intense.  Make  it  of  cotton 
which  has  been  prepared  with  especial  reference  to  inten- 
sity. After  sensitizing  wash  in  water  procured  by  melting 
ice;  this  is  more  reliable  than  the  distilled  water  usually 
procured  at  drug-stores.  The  plates  should  have  two  wash- 
ings in  this  water,  which  is  best  done  by  having  it  conven- 
iently placed  in  two  dishes ;  then  wash  under  the  tap,  and 
put  them  into  a  dish  containing  the  tea  solution,  where 
they  should  remain  one  or  two  minutes;  then  remove  them 
and  set  them  away  to  dry.  There  should  be  no  waves  or 
currents  of  air  pass  over  the  plates  while  drying,  as  they 
will  cause  ring  marks  which  will  show  in  the  negative.  In 
cold  or  damp  weather  an  oven  is  preferable  for  drying  them. 
I  have  one  so  arranged  that  it  can  be  heated  wTith  gas, 
which  answers  the  purpose  well,  drying  them  perfectly  in 
five  minutes.    I  find  that  plates  dried  in  this  way  keep 


Newton's  dry  processes. 


495 


better  and  give  more  brilliant  negatives  than  those  drying 
spontaneously. 
To  develop  these  plates  make  two  developers  as  follows: 

No.  1. 


Hot  water,  5  ounces. 

Gallic  acid,   30  grains. 

Pyrogallic  acid,   30  44 

Citric  acid,   30  " 

Glacial  acetic  acid,   30  drops. 

Saturated  solution  of  acetate  of  lead,*  10  " 


The  glacial  acetic  acid  dissolves  the  precipitate  formed 
by  adding  the  lead.  This  forms  a  very  energetic  developer. 
I  have  no  sympathy  with  those  who  advocate  slow  devel- 
opment. A  powerful  developer,  with  the  smallest  trace  of 
silver  to  start  the  picture,  I  have  found  always  to  give 
negatives  full  of  detail  without  the  hardness  so  often  found 
in  dry-plate  negatives. 

Another  great  advantage  in  the  use  of  a  strong  devel- 
oper is,  that  it  requires  much  less  time  to  expose  the 
plates. 

The  second  developer  is  made  as  follows: 

No.  2. 

Gelatine,  20  grains. 

Double  sulphate  of  iron  and  ammonia,  .  80  44 
Sulphate  of  iron,  80  44 

Soak  the  gelatine  about  fifteen  minutes  in  cold  or  tepid 
water;  then  put  the  above  together  in  a  bowl,  with  the 
soaked  gelatine,  and  pour  on  ten  ounces  of  boiling  water. 
"When  the  gelatine  and  iron  have  dissolved,  add  ten  drops 
of  concentrated  ammonia  and  shake  thoroughly;  then  add 
sufficient  glacial  acetic  acid  to  dissolve  the  precipitate, 
which  will  require  about  forty  drops ;  then  add  twenty 
grains  of  tartaric  acid. 

This  developer  should  be  about  two  weeks  old  before  it 
is  used. 

In  developing  an  exposed  plate  use  these  developers 
alternately. 

If  the  pyrogallic  and  gallic  acid  developer  is  used  first, 
the  exposure  should  be  from  four  to  six  times  as  long  as 
when  using  the  iron  developer  first. 

To  develop,  by  using  the  pyrogallic  developer  first,  pre- 
pare a  ten-grain  solution  of  nitrate  of  silver,  acidified  with 

*  The  addition  of  the  acetate  of  lead  to  a  gallic  acid  developer,  to  increase  its 
developiDg  power,  should  be  credited  to  M.  Carey  Lea. 


496 


newton's  pry  processes. 


glacial  acetic  acid  about  five  drops  to  the  ounce;  put  two 
or  three  drops  of  this — the  quantity  required  for  a  stereo- 
scopic plate — into  a  small  cup;  then  wet  the  exposed  plate, 
and  flow  sufficient  of  the  developer  over  it  to  cover  it;  let 
it  remain  from  thirty  to  sixty  seconds  and  pour  off  into  the 
dish  containing  the  silver,  and  immediately  pour  it  back 
over  the  plate  and  off  again  into  the  dish  and  then  back 
again  on  to  the  plate.  In  this  way  even  action  on  every 
part  of  the  plate  will  be  obtained;  if  the  exposure  has  been 
right  the  picture  will  immediately  appear  and  continue  to 
develop  until  most  of  the  detail  is  out.  As  soon  as  the  de- 
veloping action  ceases,  wash  the  plate  thoroughly,  and 
treat  it  the  same  as  with  the  iron.  If  the  exposure  has  been 
too  long  for  the  pyrogallic  developer,  reduce  it  until  it  is 
of  the  right  strength.  The  same  directions  will  apply  for 
the  use  of  the  iron  developer,  but  in  that  case  we  use 
double  the  quantity  of  silver  solution. 

The  negative  comes  out  under  the  iron  developer  in  ap- 
pearance the  same  as  under  the  alkaline,  and  the  exposure 
need  be  no  longer.  As  soon  as  the  detail  is  nearly  all  out, 
or  when  the  action  ceases,  wash  it  off  and  apply  the  pyro- 
gallic developer.  Care  must  be  taken  not  to  get  too  great 
intensity,  as  this  gallic  and  pyrogallic  acid  developer  gives 
a  wine-colored  negative  of  great  brilliancy  and  of  beauti- 
ful printing  qualities,  the  peculiar  color,  however,  making 
it  unnecessary  to  have  very  great  intensity.  Those  devel- 
oping dry-plates,  whether  with  a  weak  or  strong  pyrogallic 
acid  developer,  both  in  time  and  beauty  of  negative,  will 
find  a  great  advantage  by  alternating  with  a  proper  iron 
developer. 

These  tea  plates%keep,  I  should  judge,  as  well  as  tannin, 
and  produce  much  superior  negatives. 

Newton's  Opium- Tannin  Process. 

This  process  is  the  application  of  morphia,  in  tincture 
of  opium,  combined  with  tannin.  When  the  acetate  of 
morphia  was  first  introduced  in  the  production  of  dry- 
plates  as  an  accelerator,  it  was  very  soon  discovered  that 
the  plates  did  not  keep  good  for  more  than  twenty-four 
hours.  Then  I  combined  the  morphia  with  tannin,  calcu- 
lating to  retain  the  keeping  qualities  of  the  tannin  and  the 
sensitive  qualities  of  the  morphia.  It  answered  my  expect- 
ations in  that  respect,  but  the  tannin  solution  soon  changed 


DESCRIPTION  OF  APPARATUS. 


497 


and  became  unfit  for  use.  I  then  compounded  the  follow- 
ing solution: 


The  water  should  be  hot  and  the  sugar  of  milk  finely 
pulverized,  and  the  ingredients  added  to  the  water  in  the 
order  given  above.  The  addition  of  the  laudanum  causes 
a  precipitation  of  the  gum  from  the  tannin,  and  conse- 
quently filters  perfectly  clear,  differing  in  this  respect  from 
the  simple  tannin  solution.  This  solution  will  keep  for 
months  without  undergoing  any  change  that  is  perceptible ; 
and  as  a  preservative  makes  by  far  the  most  sensitive 
plates — with  perhaps  the  morphia  excepted — with  which  I 
have  ever  experimented.  They  have,  however,  the  advan- 
tage over  the  acetate  of  morphia,  as  they  keep  the  same  as 
an  ordinary  tannin  plate. 

The  same  developers  should  be  used  as  with  the  tea 
plates,  as  given  in  the  preceding  article;  but  when  using 
the  iron  developer  first,  flow  the  plate  with  a  weak  solution 
of  iron  and  then  wash  before  using  the  iron  with  silver. 
By  making  the  gallic  and  pyrogallic  acid  developer  stronger, 
the  time  of  exposure  can  be  still  further  reduced.  Ten 
grains  each  of  the  gallic  and  pyrogallic  acid  to  the  ounce 
of  water,  will  give  equally  good  negatives  with  about  two- 
thirds  the  time  of  exposure,  from  thirty  to  fifty  seconds 
being  all  that  is  required.  In  the  summer,  with  the  opium 
process  and  iron  developer,  six  seconds'  exposure  only  is 
necessary. 


Fig.  1  represents  one  of  C.  C.  Harrison's  Portrait  Lenses 
and  fig.  2  his  focusing  lens.  Fig.  3  is  one  of  the  celebrated 
Globe  Lenses,  which  are  intended  only  for  copying  and 
making  views.  Figs.  4  and  5  represent  one  of  the  Ameri- 
can Optical  Company's  carte  de  visite  cameras,  and  fig.  6 
one  of  their  universal  cameras,  which  are  very  useful  in 
galleries  where  the  amount  of  business  is  not  sufficient  to 
require  a  separate  camera  for  each  lens,  as  with  the  trouble 
of  changing  fronts,  they  can  be  used  for  large  plates,  cards 
and  copying.  Fig.  7.  is  their  universal  Ferrotype  and  card 
camera  box,  and  is  arranged  for  four  or  sixteen  small 
heads,  with  four  gem  tubes. 


Water, 

Sugar  of  milk,  . 
Tannin, 

Tincture  of  opium, 


,  6  ounces. 

i  ounce. 
40  grains. 

£  drachm, 


Description  of  Apparatus. 


498 


DESCRIPTION  OF  APPARATUS 


Fig.  8  represents  a  new  camera  stand  just  manufactured 
by  the  same  company.  It  is  made  of  thoroughly  seasoned 
black  walnut,  and  the  movements  of  the  various  parts  are 
ingenious  and,  at  the  same  time,  simple  and  easily  adjusted. 
The  top  is  tipped  by  means  of  a  sliding  rack  and  pinion, 
which  is  so  constructed  that  it  cannot  get  out  of  order, 
and  is  perfectly  firm.  The  column  is  raised  and  lowered 
by  means  of  a  snake  screw,  turned  by  a  crank,  and  remains 
firm  and  stationary  by  the  peculiar  construction  of  the 
combination  rack  and  screw. 

Figs.  9  and  10  represent  one  of  J.  Stock  &  Co.'s  view 
cameras,  with  brass  guides,  and  screw  focusing  adjustment, 
and  folding  platform;  very  portable.  Fig.  11  is  a  stereo- 
scopic camera  of  the  same  maker,  with  vertical  sliding 
front  for  adjustment  of  foreground  and  sky.  Fig.  12  shows 
Stock's  improved  instantaneous  drop,  by  means  of  which 
operators  are  enabled  to  obtain  views  with  an  instantane- 
ous exposure.  Fig.  13  is  J.  Peace's  camera  stand  made  in 
Philadelphia,  and  fig.  14  shows  an  excellent  dark  tent, 
made  by  the  American  Optical  Company.  Fig.  15  is  their 
tripod  stand  for  field  work,  and  fig.  16  their  improved  box 
for  holding  negatives  or  cleaned  glass.  Fig.  17  is  one  of 
their  whalebone  dippers,  and  fig.  18  a  plate  cleaner. 

Fig.  19  represents  a  leveling  stand  made  by  the  same 
company.  It  is  furnished  with  adjusting  screws  for  laying 
plates  with  albumen  and  fixing  collodion  pictures.  Fig.  20 
is  one  of  their  printing-frames,  and  is  so  constructed  that  a 
uniform  pressure  is  obtained.  Whitney's  printing-frame 
is  represented  by  fig.  25,  and  Pratt's  in  figs.  27,  30  and  31. 

The  Photographic  Ware  Baths  and  Dishes  are  repre- 
sented by  figs.  21  and  22.  This  ware  has  considerable 
popularity  on  account  of  its  strength,  cheapness  and  per- 
fect reliability;  it  is  as  capable  of  resisting  the  action  of 
all  chemical  solutions  as  is  glass,  and  will  last  for  years.  It 
is  highly  recommended  by  all  who  use  it,  and  can  be  had 
of  any  stock  dealer. 

Fig.  23  represents  the  Coleman  Seller's  card  press,  and 
fig.  24  an  ingenious  camera  stand.  Fig.  26  is  an  improved 
still  for  the  purpose  of  distilling  water;  it  is  furnished  by 
Edward  Parish  of  Philadelphia.  Fig.  28  is  a  print-cutter 
introduced  some  two  years  since,  but  we  believe  it  is  not 
now  to  be  had.  Fig.  29  is  a  stand  for  field  work,  and  fig. 
32  is  a  camera  stand  sold  by  J.  H.  Simmons  of  Philadelphia. 

Total  number  of  woodcuts  in  this  work  fifty-nine. 


CHAPTER  LIV. 


WEIGHTS  AND  MEASURES. 

Weights  and  capacities  in  England  and  France  are  esti- 
mated from  certain  standard  linear  measurements.  In  Eng- 
land, a  pendulum  vibrating  seconds  of  time  in  a  vacuum,  at 
the  latitude  of  London,  and  at  the  level  of  the  sea,  is  assum- 
ed as  the  standard  of  linear  dimensions ;  it  is  39.1393  inches. 
This  is  the  standard,  too,  of  all  our  measurement  of  length, 
capacity,  and  weight  in  the  United  States.  But,  like  the 
English,  we  retain  all  the  old  and  arbitrary  systems  of 
weights  and  measures  ;  whereas  the  French  have  assumed  a 
decimal  system  in  all  their  measurements  that  merits  the 
highest  praise  and  imitation.  The  linear  standard  of  the 
French,  from  which  they  derive  all  other  measurements,  is 
called  a  metre.  It  is  the  ten-millionth  part  of  a  quarter  of 
the  earth's  meridian,  and  measures  39.371  inches.  The  metre 
is  divisible  decimally  in  both  directions. 

The  connecting  link  between  the  English  linear  unit  and 
their  measures  of  capacity  and  weight  are  as  follows  : 

A  cubic  inch  of  distilled  water  weighed  in  air  with  brass 
weights  at  a  temperature  of  62°  Fahr.,  the  barometer  stand- 
ing at  30  inches,  is  equal  to  two  hundred  and  fifty-two  grains 
and  four  hundred  and  fifty-eight  one  thousandth  parts  of  a 
grain  ;  of  such  grains  5760  are  required  to  make  the  impe- 
rial standard  troy  or  apothecaries'  pound  ;  and  7000  of  such 
grains  make  the  commercial  or  avoirdupois  pound.  The 
imperial  gallon  has  a  capacity  of  277.274  cubic  inches  ;  and 
a  gallon  of  distilled  water,  as  above,  weighs  10  pounds 
avoirdupois,  or  70,000  grains. 

The  connecting  link  between  the  French  linear  unit  and 
their  measures  of  weight  and  capacity,  are  as  follows : 

A  cubic  centimetre  of  distilled  water,  at  its  maximum 
density,  at  the  temperature  of  39.5°  Fahrenheit,  is  the  unit 
of  weights  and  is  called  a  gramme,  which  is  divided  deci- 
mally above  an.d  below. 

A  cubic  decimetre  is  called  a  litre,  which  is  the  unit  of  the 
measures  of  capacity,  and  divisible  decimally. 
23 


500 


WEIGHTS  AND  MEASURES. 


Comparison  of  Weights  and  Measures, 

Apothecaries'  Weight. 


20  grains 
60  grains 
480  grains 
6760  grains 


3  scruples  = 
8  drachms  = 
12  ounces  = 


1  grain 
1  scruple 
1  drachm 
1  ounce 
1  pound 


French  gramme, 
=  0.0647 
=  1.295 
=b  3.885 
s=  31.08 
=  372.96 


Symbols. 

Grain  =  gr.    Scruple  =  3.   Drachm  =  3  .    Ounce  =  § .   Pound  : 


Apothecaries'  Measure  of  Capacity.    (United  States.) 

1  fluid  drachm. 
=    1  fluid  ounce. 
—    1  pint. 
=    1  gallon. 


60  minims  = 

480  minims  =    8  fluid  drachms 

7680  minims  =16  fluid  ounces 

61,440  minims  s=    8  pints 


16  drachms 
16  ounces 
112  pounds 
20  hundred  weight 


Avoirdupois  Weight. 

1  drachm 

=b  1  ounce 
—    1  pound 

1  hundred  weight 
1  ton 


French  gramme. 
=  1.77 
=  28.328 
sb  453.25 


1  drachm  s= 

1  ounce  =s 

1  pound  = 

1  hundred  weight  = 

1  ton  s= 


Apothecaries'  grains. 
=  27.34375 


437.5 
7000. 
784000. 
15680000. 


Apothecaries'  ounce 
Avoirdupois  ounce 
United  States  pint 
Imperial  or  British  pint 
United  States  gallon 


480  grains. 
437.5  grains. 

16  fluid  ounces. 

20  fluid  ounces. 
128  fluid  ounces.  = 


Imperial  or  British  gallon  =160  fluid  ounces  =  10 

Weight  of  Water  at  62°  and  Capacity  of : 


8  pounds  aroirdipj 


Cubic  inches. 

Grains, 

1  gallon  (Imperial) 

277.274 

70000. 

1  gallon  (U.  S.) 

231.000 

56000. 

1  quart  (Imperial) 

69.318 

17500. 

1  quart  (U.  S.) 

57.750 

14000. 

1  pint  (Imperial) 

34.659 

8750. 

1  pint  (U.  S.) 

28.875 

7000. 

16  fluid  ounces 

28.875 

7000. 

1  fluid  ounce 

1.732 

437.5 

1  fluid  drachm 

0.216 

54.7 

1  minim 

0.0386 

0.91 

WEIGHTS  AND  MEASURES. 


501 


French  Measures  of  Length. 

English  inches. 
Millimetre      =  .03937 
Centimetre      =  .39371 
Decimetre      =  3.93708 
Metre  =  39.37079 

Decametre      =       393.70788  ' 
Hectometre     =  3937.0788 
Kilometre      =  39370.788 
Myriametre     ==  393707.88 

French  Weights. 

Equivalents  in  Grain*. 

Milligramme,   .0154 

Centigramme,  .    .       ....  .1543 

Decigramme,    1.5434 

Gramme,  .  15.434 

Decagramme,   154.340 

Hectogramme,   1543.402 

Kilogramme,   15434.023 

Myriogramme   154340.234 

A  gramme  of  water  =  1  cubic  centimetre  =  15.43  grains  =17  minims. 
1000  grammes  of  water  =  1  litre  =  1  kilogramme  =  15434.023  grains  =s 
2  lb.  3.27  oz. 

French  Liquid  Measures.    United  States  Liquid  Measure*. 
Cubic  incites. 

Millilitre,  ....  .0610    16.2318  minims. 

Centilitre,    .    .    .  .6103    2.7052  fl.  drachms. 

Decilitre,  ....  6.1028    3.3816  fl.  ounces. 

Litre,   61.028    2.1135  pints. 

Decalitre,  .    .       .       610.280    2.6419  gallons. 

Hectolitre,    .    .    .       6102.80    26.4190  " 

Kilolitre,   ....    61028.0    264.1900  " 

Myrialitre,    .   .    .    610280   2641.9000  * 


CHAPTER  LV. 


COMPARISON    OP    THERMOMETRY    INDICATIONS    ON  TUB 
PRINCIPAL   THERMOMETERS   IN  USE. 

Thermometers  are  instruments  for  ascertaining  the  tem- 
perature of  bodies,  whether  liquid,  solid,  or  gaseous.  The 
principal  thermometers  in  use  are  :  the  Centigrade,  which 
is  used  principally  in  France ;  Reaumur's  thermometer,  of 
more  especial  use  in  Germany ;  and  Fahrenheit's  thermome- 
ter, used  more  especially  in  Great  Britain  and  the  United 
States. 

The  temperature  of  boiling  water  is 
100°  on  the  Centigrade  scale. 

80°  on  Reaumur's  scale. 
212°  on  Fahrenheit's  scale. 

The  freezing  point  of  water  is  indicated  by 
0°  on  the  Centigrade  scale. 
0°  on  Reaumur's  scale. 
32°  on  Fahrenheit's  scale. 

7%e  number  of  degrees  between  the  freezing  point  and  the  boiling  point  is 
100°  on  the  Centigrade  scale. 

80°  on  Reaumur's  scale. 
180°  on  Fahrenheit's  scale. 

To  reduce  Centigrade  degrees  to  those  of  Reaumur. 
Rule :  Multiply  by  4  and  divide  by  5. 
To  reduce  Reaumur's  degrees  to  those  of  the  Centigrade. 
Rule :  Multiply  by  5  and  divide  by  4. 
To  reduce  Centigrade  degrees  to  those  of  Fahrenheit. 
Rule :  Multiply  by  9,  divide  by  5,  and  add  32  to  the  quotient. 
To  reduce  Fahrenheit's  degrees  to  those  of  the  Centigrade. 
Rule  :  Subtract  32,  multiply  the  difference  by  5,  and  divide  by  9. 
To  reduce  Reaumur's  degrees  to  those  of  Fahrenheit. 
Rule  :  Multiply  by  9,  divide  by  4,  and  add  32  to  the  quotient. 
To  reduce  Fahrenheit's  degrees  to  those  of  Reaumur. 
Rule :  Subtract  32,  multiply  the  difference  by  4,  and  divide  by  9. 


COMPARISON  OF  THERMOMETRY  INDICATIONS. 


503 


Table  of  the  corresponding  degrees  on  the  Scales  of  Fahren- 
heit^ Reaumur,  and  the  Centigrade. 


JXtjllU/lllUI  • 

"Rfttlinc  "nnint.  919. 

80 

100 

203 

7fi 

95 

194 

72 

90 

185 

68 

85 

176 

64 

80 

167 

60 

75 

158 

56 

70 

149 

52 

65 

140 

48 

60 

131 

44 

55 

122 

40 

50 

113 

36 

45 

104 

32 

40 

95 

28 

35 

86 

24 

30 

77 
1 1 

20 

25 

63 

16 

20 

59 

12 

15 

50 

3 

10 

41 

4 

5 

82 

0 

0 

23 

—4 

—5 

14 

—8 

—10 

5 

—12 

—15 

—4 

—16 

—20 

—13 

—20 

—25 

—22 

—24 

—30 

—31 

—28 

—35 

—40 

—32 

—40 

All  the  intermediate  indications  can  be  obtained  by  the 
use  of  the  preceding  rules. 


CHAPTER  LVL 

COMPARISON   OF   HYDROMETRIC   AND   SPECIFIC  GRAVITY 
INDICATIONS. 

The  specific  gravity  of  a  body  is  the  comparison  of  the 
weight  of  a  given  bulk  of  the  said  substance  with  that  of  an 
equal  bulk  of  distilled  water  at  62°  Fahrenheit.  Gases  are 
compared  either  with  air  as  the  standard  or  with  distilled 
water. 

The  specific  gravity  of  a  body  is  taken  by  special  instru- 
ments for  this  purpose ;  some  of  these  instruments  are  de- 
nominated Hydrometers,  and  give  arbitrary  indications, 
which  have  to  be  reduced  afterward  in  terms  of  specific 
gravity. 

Baum6's  Hydrometers  are  in  extensive  use  in  France,  and 
Twaddell's  Hydrometer  in  England.  Baume  has  two  Hy- 
drometers :  one  for  liquids  heavier  than  water,  and  one  for 
liquids  lighter  than  water. 


For  Liquids  Heavier  than  Water.  Baume* . 


Deg. 

Sp.  Grav. 

Deg. 

Sp.  Grav. 

Deg. 

Bp.  Grav. 

Deg. 

Sp.  Grav. 

0 

. .  1.000 

20  . 

...  1.152 

40  .. 

. .  1.357 

60  .. 

..  1.652 

1  ... 

, .  1.007 

21  . 

...  1.160 

41  .. 

. .  1.369 

61  .. 

. .  1.670 

2  .. 

. .  1.013 

22  . 

...  1.169 

42  .. 

. .  1.381 

62  .. 

. .  1.689 

3  .. 

. .  1.020 

23  . 

...  1.178 

43  .. 

..  1.395 

63  .. 

. .  1.708 

i  .. 

. .  1.027 

24  . 

...  1.188 

44  .. 

. .  1.407 

64  .. 

. .  1.727 

5  .. 

. .  1.034 

25  . 

...1.197 

45  .. 

. .  1.420 

65  .. 

. .  1.747 

6  .. 

. .  1.041 

26  . 

. . .  1.206 

46  .. 

. .  1.434 

66  .. 

. .  1.767 

7  . . 

. .  1.048 

27  . 

...  1.216 

47  .. 

. .  1.448 

67  .. 

. .  1.788 

8  .. 

1.056 

28  . 

...  1.225 

48  .. 

. .  1.462 

68  .. 

. .  1.809 

9  .. 

..  1.063 

29  . 

...  1.235 

49  .. 

. .  1.476 

69  .. 

. .  1.831 

10  .. 

. .  1.070 

30  . 

. . .  1.245 

50  .. 

. .  1.490 

70  .. 

. .  1.854 

11  .. 

. .  1.078 

31  . 

...  1.256 

51  .. 

. .  1.805 

71  .. 

. .  1.877 

12  .. 

. .  1.085 

32  . 

...  1.267 

52  .. 

. .  1.520 

72  .. 

. .  1.900 

13  .. 

. .  1.094 

33  . 

...  1.277 

53  .. 

..  1.535 

73  .. 

1.924 

14  .. 

. .  1.101 

34  . 

...  1.288 

54  .. 

. .  1.551 

74  .. 

. .  1.949 

15 

. .  1.109 

35  . 

...  1.299 

55  .. 

1.567 

75  .. 

. .  1.974 

16  .. 

..  1.118 

36  . 

...  1.310 

56  .. 

..  1.583 

76 

. .  2.000 

VI  .. 

..  1.126 

37  , 

...  1.321 

57  .. 

..  1.600 

> 

..  1.134 

38  . 

. . .  1.333 

58  .. 

..  1.617 

1  i 

1.143 

39  . 

. . .  1.345 

59 

. .  1.684 

HYDROMETBIC  INDICATIONS. 


505 


For  Liquids  Lighter  than  Water.  BaumJk. 


Deg. 

Sp.  Grav. 

Deg. 

Sp.  Grav. 

Beg. 

Sp.  Grav. 

Deg. 

Sp.  Grow. 

10  . 

. . .  1.000 

23 

..  0.918 

36  .. 

. .  0.849 

49  . 

. . .  0.789 

11  . 

. . .  0.993 

24 

..  0.913 

37 

. .  0.844 

50  . 

. . .  0.785 

12  . 

. . .  0.987 

25  .. 

. .  0.907 

38  .. 

. .  0.839 

51  . 

...  0.781 

13  . 

. . .  0.980 

26  .. 

. .  0.901 

39  .. 

. .  0.834 

52  . 

. . .  0.777 

14  . 

. . .  0.973 

27  .. 

. .  0.896 

40  .. 

. .  0.830 

53  . 

...  0.773 

15  . 

. . .  0.967 

28  . . 

. .  0.890 

41  .. 

..  0.825 

54  . 

...  0.768 

16  . 

. . .  0.960 

29  .. 

. .  0.885 

42  .. 

. .  0.820 

55  . 

. . .  0.764 

IT  . 

. . .  0.954 

30  .. 

..  0.880 

43  .. 

..  0.816 

56  . 

. . .  0.760 

18  . 

. . .  0.948 

31  .. 

. .  0.874 

44  .. 

0.811 

57  . 

. . .  0.757 

19 

. . .  0.942 

32  .. 

. .  0.869 

45  .. 

. .  0.807 

68  . 

. . .  0.753 

20  . 

. . .  0.936 

33 

. .  0.864 

46  .. 

. .  0.802 

59  . 

. . .  0.749 

21  . 

. . .  0.930 

34  .. 

. .  0.859 

47 

. .  0.798 

60  . 

. . .  0.745 

22  . 

. . .  0.924 

35  .. 

. .  0.854 

48  .. 

. .  0.794 

61  . 

. . .  0.741 

TwaddelVs  Hydrometer. 

The  degrees  on  Twaddell  are  converted  into  equivalent 
specific  gravities  by  multiplying  them  by  5  and  adding 
1000 ;  then  mark  off  three  figures  as  decimals. 


Deg. 

Sp.  Grav. 

Deg. 

Sp.  Grav. 

Deg. 

Sp.  Grav. 

Deg. 

Sp.  Grav, 

1  .. 

. .  1.005 

8  .. 

. .  1.040 

15  .. 

. .  1.075 

22  .. 

..  1.110 

2 

1.010 

9  .. 

. .  1.045 

16  .. 

. .  1.080 

23  .. 

..  1.115 

3  .. 

1.015 

10  .. 

. .  1.050 

17  .. 

. .  1.085 

24 

..  1.120 

4  .. 

. .  1.020 

11  .. 

.  .  1.055 

18  .. 

. .  1.090 

26  .. 

..  1.125 

6  .. 

. .  1.025 

12  .. 

. .  1.060 

19  .. 

. .  1.095 

26 

1.130 

6  .. 

. .  1.030 

13  .. 

. .  1.065 

20  .. 

. .  1.100 

27 

1.135 

..  1.085 

14  .. 

. .  1.070 

21  .. 

..  1.105 

28 

. .  1.140 

CHAPTER  LVII. 


TABLE    OF   THE   ELEMENTS    OF   MATTER,   "WITH  THEIR 
SYMBOLS  AND  CHEMICAL  EQUIVALENTS. 


^Elements.  Symbol. 

Aluminum,  .   Al. 

Antimony,  (Stibium,).. .  .Sb. 

Arsenic,  As. 

Barium,  Ba. 

Bismuth,  Bi. 

Boron,  B. 

Bromine,  Br. 

Cadmium,  Cd. 

Caesium,  Cae. 

Calcium,  . . .  Ca. 

Carbon,  C. 

Cerium,  Ce. 

Chlorine,  CI. 

Chromium,  Cr. 

Cobalt,  Co. 

Columbium,  (Tantalum,). .  Ta. 

Copper,  (Cuprum,)  Cu. 

Didymium,  Di. 

Erbium,  Er. 

Fluorine,  F. 

Glucinum, .  .v.  Gr. 

Gold,  (Aurum,)  Au. 

Hydrogen,  H. 

Ilmenium,  II. 

Iodine,  .1. 

Iridium,  Ir. 

Iron,  (Ferrum,)  Fe. 

Lanthanum,  La. 

Lead,  (Plumbum,)  Pb. 

Lithium,  Li. 

Magnesium,  Mg. 

Manganese,  Mn. 

Mercury,  (Hydrargyrum,)  Hg. 


Chem. 


14 

129 
15 
69 

213 
11 
IS 
56 

123 
20 
6 
46 
36 
26 
30 

184 
32 
48 
? 

19 
1 

197 
1 

126 
99 
28 
44 

104 
1 
12 
28 

100 


Elements. 

Molybdenum,  Mo. 

Nickel,  Ni. 

Niobium,  Nb. 

Nitrogen,  N. 

Norium,  No. 

Osmium,  Os. 

Oxygen,  O. 

Palladium,  Pd. 

Pelopium,  Pe. 

Phosphorus,  P. 

Platinum,..  Pt. 

Potassium,  (Kalium,). . .  ,K. 

Rhodium,  Ro. 

Rubidium,  Kb. 

Ruthenium,  Ru. 

Selenium,  Se. 

Silicon,  Si. 

Silver,  (Argentum,)  Ag. 

Sodium,  (Natrium,)  Na. 

Strontium,  Sr.; 

Sulphur,   S. 

Tellurium,  Te. 

Terbium,  Tb. 

Thorium,  Th. 

Tin,  (Stannum,)  Sn. 

Titanium,  Ti. 

Tuogsten  (Wolfram,). . .  .W. 

Uranium,  U. 

Vanadium,  V. 

Yttrium,  Y. 

Zinc,  Zn. 

Zirconium,  Zr. 


Chem. 

Equiv. 
38 
30 

14 


32 
99 
39 
52 
85 
52 
40 
22 
108 
23 
44 
16 
64 
? 

60 
59 
24 
92 
60 
68 
32 
32 
34 


The  Elements  printed  in  italics  are  the  Metalloids;  the 
rest  are  the  Metals. 


CHAPTEK  LVIII. 


THE   SEVENTH   EDITION  ADDITIONS    THERETO  HERR  ALBERT^ 

MECHANICAL  PRINTING  PROCESS  SARONY's  PHOTO-CRAYON  POR- 
TRAITS— PRINTING  WITH  COLLODIO-CHLORIDE  OF  SILVER  ON 
PAPER  AND  OPAL  GLASS — PRINTING  ON  PAINTED  CANVAS. 


THE  SEVENTH  EDITION. 

We  will  here  commeilce  our  additions  to  the  Seventh 
Edition  of  The  Silver  Sunbeam.  There  will  be  found  con- 
siderable information  in  the  following  new  processes  which 
have  appeared  since  our  Sixth  Edition  was  published,  and 
as  we  are  anxious  that  this  work  shall  be  a  complete  store- 
house of  photographic  knowledge,  we  shall  give  in  each 
edition  everything  new  in  the  art  up  to  the  time  of  our 
going  to  press.    We  will  commence  with:  — 

herr  Albert's  mechanical  printing  process. 

Herr  Albert's  process  is  analogous  to  that  of  Tessie  du 
Motay  and  Mareschal,  and  both  are  allied  to  photo-lithog- 
raphy ;  but  as  a  film  of  gelatine  is  made  to  acquire  pro- 
perties resembling  those  of  the  lithographic  stone,  we 
propose  that  processes  of  this  kind  should  be  styled  photo- 
collography.  The  principle  upon  which  this  method  of 
printing  is  based  may  be  explained  as  follows  : — 

A  plate  is  covered  with  a  solution  of  gelatine  and  a 
chromic  salt,  dried,  and  exposed  under  a  negative.  It  is 
then  washed  in  cold  water,  not  with  a  view  to  remove  any 
portion  of  the  gelatine,  but  simply  to  get  rid  of  the  chro- 
mic salt,  and  to  permit  the  gelatine  to  become  saturated 
with  moisture,  which  it  will  absorb  in  the  inverse  ratio  of 
the  action  of  light;  that  is,  the  portions  of  the  gelatine 
coating  which  have  been  very  fully  exposed — such  as  the 
deepest  shadows  of  the  image — will  have  been  rendered 
insoluble  and  impermeable  to  water;  those  parts  upon 
24 


508      herb  Albert's  mechanical  printing  process. 


which  the  action  of  light  has  been  less  complete  absorb 
water  in  just  such  degree  as  they  have  been  rendered 
partially  insoluble  and  impermeable ;  whilst  the  parts 
completely  protected  from  light  absorb  water  freely.  This 
film,  after  treatment  with  water,  is  just  in  the  condition  of 
a  moistened  lithographic  stone.  If  a  roller  charged  with 
greasy  ink  be  applied  to  its  surface,  the  ink  will  be  repelled 
by  the  moist  portions,  but  will  adhere  to  the  dry  or  insol- 
uble portions,  as  it  would  to  the  greasy  image  on  the  stone. 
The  ink  adheres  to  the  image  in  the  exact  ratio  of  its  free- 
dom from  moisture.  In  the  deep  shadows,  where  light 
has  acted  fully,  the  film  having  become  quite  insoluble  and 
unabsorbent,  the  ink  adheres  freely ;  to  the  parts  partially 
moistened  it  adheres  less  perfectly ;  and  so  on  in  exact  rela- 
tion, the  action  of  the  light  on  the  film  being  registered 
by  degrees  of  impermeability  or  permeability  to  moisture, 
and  these  degrees  of  permeability  again  registered  by  the 
reception  or  rejection  of  a  fatty  ink  applied  to  the  surface. 
An  exact  transcript  of  the  negative  is  thus  secured  in 
printing  ink  on  the  layer  of  gelatine,  and  a  sheet  of  paper 
being  placed  upon  it  and  suitable  pressure  applied,  a  print 
is  produced. 

The  details  of  Herr  Albert's  process,  briefly  stated,  as 
given  in  the  French  specification,  are  as  follow  : — A  thick 
plate  of  glass,  about  five-eighths  of  an  inch  in  thickness, 
is  used  for  receiving  the  printing  surface.  The  glass  is 
coated  with  the  following  preparation : — 

Filtered  water,   300  parts. 

Albumen  150  " 

Gelatine,  '  15  " 

Bichromate  of  potash,  •   .   .     8  11 

The  glass  coated  with  this  solution  is  dried,  and  a  piece  of 
black  cloth  placed  behind  it,  after  which  it  is  exposed  to 
light  for  some  time — our  correspondent  thinks  about  two 
hours.  Next  a  coating  of  gelatine  and  bichromate  solution 
is  applied,  as  follows: — 

Gelatine,   300  parts. 

Bichromate,  100  " 

Water,  180  " 

It  is  evident  that  an  error  is  made  in  stating  the  amount 
of  water,  as  the  gelatine  and  bichromate  could  not  be  dis- 
solved in  so  small  a  proportion;  it  is  probable  that  one 
figure  has  been  omitted,  and  that  instead  of  180  parts, 
1,800  should  be  read,  as  with  the  latter  proportion  of  water 


sarony's  photo-crayon  portraits. 


509 


a  workable  solution  could  be  made.  The  plate  is  coated 
with  the  solution  of  gelatine  and  bichromate,  dried,  and 
exposed  under  a  negative,  care  being  taken  to  secure 
direct  rays.  After  sufficient  exposure  the  plate  is  washed; 
it  is  then  treated  as  a  lithographic  stone — that  is,  it  is 
coated  with  a  fatty  ink  by  means  of  a  roller  —  and  im- 
pressions printed  by  means  of  a  lithographic  or  other  press. 

sarony's  photo-crayon  portraits. 

This  new  style  of  portraiture  consists  in  using  the  image 
as  a  transparency  enlarged  from  a  small  negative.  It  is  a 
vignetted  image,  and  is  backed  with  crayon  paper  with  a 
hatched  vignetted  design,  giving  the  effect  of  a  fine  crayon 
drawing.  The  important  point  in  the  character  of  the 
transparency  is,  that  it  shall  be  thin,  delicate,  bright  and 
clear,  so  as  to  form  a  good  picture  when  backed  up  and 
viewed  by  reflected  light.  In  producing  it  the  idea  must 
be  constantly  kept  in  mind  that  a  picture  to  be  looked  aty 
not  to  be  looked  through,  is  required.  The  quality  of  image, 
in  fact,  is  needed  which  answers  best  for  Eburneum  pictures 
or  transferred  collodion  prints. 

There  should  be  no  trace  of  fog;  the  highest  lights  must 
be  perfectly  clear,  bare  glass;  and  from  that  the  more  gra- 
dation, of  course,  the  better. 

A  good  commercial  bromo-iodized  collodion  is  used; 
one  which  is  tolerably  ripe  will  answer  best,  and  if  any 
tendency  to  deposit  on  the  shadows  is  present,  the  addi- 
tion of  a  little  tincture  of  iodine  to  the  collodion  will  be 
found  useful.  Excite  in  a  strong  bath  containing  (say) 
from  thirty-five  to  forty  grains  per  ounce,  slightly  acid 
with  nitric  acid.  The  time  of  immersion  should  be  short. 
A  short  immersion,  which  leaves  a  portion  of  the  iodide 
and  bromide  unconverted  into  salts  of  silver,  is  the  essen- 
tial condition  of  brilliancy  and  freedom  from  foggy  de- 
posit. 

A  moderately  full  exposure  is  desirable.  The  developer 
consists  of — 

Pyrogallic  acid,  1  grain. 

Citric  acid,   1£  grains. 

Water  1  ounce. 

Alcohol,   quantum  suff. 

The  addition  of  acetic  acid  and  tartaric  acid  often  improves 
the  tone.    Great  care  must  be  exercised  not  to  carry  the 


510         PRINTING  WITH  COLLODIO-CHLORIDE  OF  SILVER. 


development  too  far,  as  over-development  causes  the  de- 
tail to  appear  buried,  and  only  visible  by  transmitted  light. 
Fix  with  hyposulphite. 

If  the  chemicals  are  in  good  condition  and  the  develop- 
ment is  rightly  managed,  a  picture  of  good  quality  and 
satisfactory  warm  brown  color  is  produced  without  toning; 
but  in  most  cases  some  toning  will  be  necessary.  Various 
methods  are  possible,  few  exceeding  gold  toning  as  used 
by  Mr.  Burgess.  Mercury  and  hypo  can  also  be  used  for 
toning.  When  the  right  tone  is  produced,  wash,  dry, 
and  finally  varnish. 

PRINTING  WITH  COLLODIO-CHLORIDE  OF  SILVER  ON  PAPER  AND 
OPAL  GLASS.  BY  G.  WHARTON  SIMPSON. 

Many  photographers  have  made  extensive  application  of 
our  collodio-chloride  process,  some  preparing,  by  its  means, 
for  sale,  a  very  excellent  sensitive  paper,  ready  for  use.  It 
has  also  been  extensively  used  in  producing  enlarged  nega- 
tives. We  here  subjoin  brief  and  simple  formulae,  which 
we  have  found  successful: — 

Mix  three  stock  solutions — 


No.  1. — Nitrate  of  silver,  1  drachm. 

Distilled  water,  1  " 

No.  2. — Chloride  of  strontium,  64  grains. 

Alcohol,  2  ounces. 

No.  3.— Citric  acid,  64  grains. 

Alcohol,  ,    .   .      2  ounces. 


Now  to  every  two  ounces  of  collodion  add  thirty  drops  of 
No.  1  solution,  previously  mixed  with  one  drachm  of  alco- 
hol; then  one  drachm  of  No.  2  solution  gradually,  shaking 
well  at  the  same  time;  lastly,  half  a  drachm  of  No.  3  solu- 
tion.   In  a  quarter  of  an  hour  it  will  be  fit  to  use. 

Paper. 

A  sizing  of  gum  tragacanth  should  be  applied  to  the 
paper,  to  render  it  non-absorbent. 

In  applying  the  collodio-chloride,  about  one-eighth  of 
an  inch  is  turned  up  all  round,  leaving  a  corner  from  which 
to  pour.  The  paper  is  attached  by  pins  to  a  flat  board, 
and  coated  as  a  glass  plate  would  be.  It  should  dry  very 
thoroughly  before  being  placed  in  contact  with  the  neg- 
ative. 

M.  de  Constant  has  found  that  prints  are  much  improved, 
if  the  sensative  paper  or  glass  is  fumed  with  ammonia  ; 


PRINTING  WITH  C0LL0DI0-CHL0RIDE  OF  SILVER.  511 

and  Dr.  Monckhoven  points  out  that  fuming  prevents  so- 
larization,  or  the  formation  of  a  light-brown  by  over  print- 
ing. 

Opal  Glass. 

Flashed  patent  plate  answers  best.  It  should  not  under 
any  circumstances,  receive  a  preliminary  coating  of  albu- 
men, which  is  a  source  of  fading. 

Preparing  the  Plate. 

The  plate  should  be  quite  clean.  We  have  found  that 
running  an  edging  of  dilute  albumen  all  round,  and  allow- 
ing it  to  dry  before  coating  the  plate,  prevents  the  loss  of 
the  film  in  toning,  fixing,  &c.  After  the  film  of  collodio- 
chloride  has  set,  we  finish  chying  before  a  bright  fire, 
taking  care  that  the  thick  edge  where  the  plate  was  drained 
is  quite  dry,  or  the  negative  will  be  injured.  The  plate  is 
left  a  few  minutes  to  cool,  and  is  then  placed  in  the  print- 
ing-frame. 

Printing. 

It  is  better  to  use  one  of  the  many  printing-frames  made 
for  the  purpose,  which  permit  the  progress  of  printing  to 
be  examined  without  risk  of  movement.  The  printing 
should  be  a  little  deeper  than  is  required  for  albumenized 
paper. 

Toning,  Fixing  and  Washing. 

If  the  edging  of  dilute  albumen  has  not  been  used,  an 
edging  of  a  solution  of  wax  should  now  be  run  round  the 
film,  and  this  will  prevent  it  from  slipping  or  becoming 
loose.  An  old  and  dilute  acetate  bath  answers  best  ;  but 
any  toning  bath  may  be  used,  provided  it  is  not  too  active, 
as  in  some  cases  the  image  tones  in  a  few  seconds  to  a 
slate  color,  and  is  spoiled.  It  is  generally  important  that 
the  bath  should  be  weak  and  old.  A  bath  of  hypo  and 
gold  also  answers  well.  Fix  in  a  solution  of  hypo  three 
ounces  to  a  pint  of  water.  Five  minutes'  immersion  is 
generally  sufficient.  Wash  for  five  minutes  under  a  tap. 
The  prints  should  not  be  toned  deeper  than  a  warm  brown 
or  purple,  as  they  lose  no  depth  in  the  hypo,  and  are 
blacker  after  drying. 

Dr.  Liesegang  recommends  chloride  of  lithium  instead 
of  chloride  of  strontium,  and  we  have  found  the  results 
good,  but  not  better  than  with  our  own  formula.  The 


512 


PRINTING  ON  PAINTED  CANVAS. 


lithium  salt  is  more  soluble  in  alcohol  and  ether  than  the 
strontium  salt  ;  and  little  more  than  half  of  the  former  is 
required,  since  forty-one  parts  of  chloride  of  lithium  con- 
tain as  much  chloride  as  seventy-nine  parts  of  chloride  of 
strontium. 

Collodio- Chloride  made  Useful  for  Printing  on  Ivory. 

No  modification  of  the  formula  is  required  :  a  sample  of 
collodio-chloride  which  works  well  on  paper  or  opal  glass 
will  give  admirable  pictures  on  ivory.  The  prepared  ivory 
is  coated  with  collodio-chloride,  and  when  dry,  is  printed, 
toned,  and  fixed  in  the  same  manner  as  a  picture  on  opal 
glass.  The  film  adheres  with  sufficient  tenacity  to  render 
any  edging  of  varnish  unnecessary.  A  more  perfect  wash- 
ing to  remove  the  hyposulphite  is  necessary  than  with 
opal  glass,  because  of  the  more  absorbent  character  of  the 
ivory. 

A  NEW  PROCESS  FOR  PRINTING  ON  PAINTED  CANVAS.  

BY  W.  T.  BOVEY. 

In  a  former  publication  of  mine,  I  made  known  a 
method  of  printing  on  artist's  canvas  ;  but  the  process  is 
so  beset  with  difficulties  that  failure  has  proved  the  rule, 
success  the  exception,  with  experimentalists  who  have 
worked  by  my  directions.  Desirous  of  simplifying  what 
must  prove  a  valuable  process,  I  have  labored  on  patiently 
until  the  working  out  of  the  method  I  am  about  to  describe, 
which'leaves  nothing  to  be  desired  in  the  quality  of  the 
print  it  is  capable  of  producing. 

First,  saturate  strong  methylated  alcohol  with  soft  soap 
(it  is  sold  by  all  chemists),  allow  the  excess  of  soap  to  sub- 
side, then  decant  the  clear  liquid.  Next,  take  zinc  white 
(dry),  place  in  a  mortar,  add  about  ten  grains  of  pure 
chloride  of  calcium  to  each  ounce  of  the  pigment,  triturate 
to  a  fine  powder,  and  mix  to  the  consistency  of  a  paste 
with  the  alcohol  and  soap  solution.  Grind  with  a  pestle 
as  fine  as  possible.  Thin  with  spirits  of  turpentine  to 
which  a  little  linseed  or  nut  oil  has  been  added  ;  a  very 
small  quantity  of  a  quick-drying  varnish  or  japanner's  gold 
size  should  be  added  also,  to  " stay"  the  pigment,  which  is 
then  ready  for  use.  Select  painted  canvas,  known  to  the 
trade  as  single  primed.  Brush  on  the  pigment  in  the 
usual  way  with  an  ordinary  paint  brush.    When  the  whole 


PRINTING  ON  PAINTED  CANVASS. 


513 


surface  of  the  canvas  is  covered  with  the  pigment,  cross 
and  recross  with  the  brush  rapidly  and  light-handed,  and 
finish  by  removing  the  brush  marks  with  a  grainers' 
badger. 

[Note. — Those  who  are  not  skilled  in  the  handling  of  a 
paint  brush  would  do  well  to  entrust  the  work  to  some  in- 
telligent house  painter  or  decorator. J 

When  dry,  the  canvas  is  ready  for  sensitizing.  Sensi- 
tize by  floating  on  the  silver  bath,  strength  sixty  grains 
per  ounce,  in  the  ordinary  way.  If  too  much  oil  has  not 
been  mixed  with  the  pigment,  it  takes  kindly  to  the  silver 
bath.  Should  there,  however,  be  any  sign  of  glaze  when 
the  paint  is  dry,  the  surface  of  the  canvas  should  be 
rubbed  with  a  wet  sponge,  previous  to  sensitizing,  until 
all  trace  of  greasiness  is  removed,  otherwise  the  canvas 
would  be  unevenly  sensitive,  and  the  picture  would  be 
spotty. 

The  printing  should  be  permitted  to  be  deeper  than 
needed  in  the  finished  picture.  Tone,  if  desired,  by  any 
of  the  usual  formulae.  Fix  in  hypo,  eight  ounces  to  a  pint 
of  water.  Wash  thoroughly  and  dry.  If  care  be  observed 
the  operations  may  be  executed  without  wetting  the  back 
of  the  cloth  until  the  final  washing. 

Caution, 

Use  as  little  oil  as  possible,  or  the  pigment  will  resist 
the  action  of  the  hypo,  and  the  picture  will  remain  unfixed 
and  the  paint  will  continue  sensitive. 


CHAPTEE  LIX. 


ADVANTAGES  OF  A  SUBSTRATUM  FOR  THE  COLLODION  FILM — 
CHROMO-PHOTOGRAPHY  OR  PHOTO-MINIATURE  A  SIMPLE  APPA- 
RATUS FOR  ENLARGEMENTS  PHOTOGRAPHING  MACHINERY. 

ON  THE  ADVANTAGES   OF    A   SUBSTRATUM    FOR    THE  COLLODION 
FILM.  BY  SAMUEL  FRY. 

Anything  that  tends  to  reduce  the  manipulatory  diffi- 
culties of  photography  is  a  direct  assistance  to  more 
artistic  productions,  by  enabling  the  operator  to  free  his 
mind  from  mechanical  details,  and  devote  his  energies  en- 
tirely to  his  composition.  Now,  with  a  great  number  of 
persons,  matters  of  continual  difficulty  occur  by  such 
things  as  spots,  comets,  dirty  plates,  film  splitting  off,  and 
such  like  matters.  And  yet  a  very  simple  plan  exists  for 
getting  rid  of  all  fear  of  any  one  or  all  of  those  trouble- 
some visitations.  This  plan  is  not  new  ;  it  was  proposed 
years  ago,  and  lately  revived  in  the  Photographic  News, 
whence  I  took  it.  It  is  simply  to  coat  the  plates  with 
dilute  albumen  before  taking  pictures.  You  have  thus  a 
pure,  uncontaminated  surface  to  work  upon  :  nothing  has 
ever  touched  it.  The  following  advantages  are  claimed  for 
such  procedure,  and  the  writer  is  stating  his  own  experi- 
ence in  asserting  that  they  are  really  found  by  the  use  of 
albuminous  substratum  : 

A  complete  absence  of  spots,  comets,  or  markings  of  any 
kind  on  the  plate  (to  test  this,  take  a  plate  known  to  be 
dirty,  and  coat  one  side  only  with  albumen) ;  great  adhe- 
siveness to  the  plate  ;  a  better  printing  color  ;  a  perfect 
cleanness  of  picture,  and  complete  transparency  of  shadows 
on  those  parts  not  acted  on  by  light ;  every  plate  is  like 
a  new  patent  plate  glass  ;  great  labor  in  plate  cleaning 
and  polishing  is  saved,  as  the  plates  only  require  rinsing 
and  drying. 


ADVANTAGES  OF  A  SUBSTRATUM  FOR  THE  COLLODION  FILM.  515 

I  take  one  white  of  egg  to  ten  ounces  of  water,  and  a 
small  quantity  of  liquor  ammonia,  and  after  the  usual  agi- 
tation, filter  very  carefully.  The  plates  are  dusted,  and  a 
small  pool  formed  in  the  middle  ;  this  is  guided  over  by  a 
piece  of  glass  a  quarter  of  an  inch  narrower  than  the 
plate.  The  albumen  should  not  quite  reach  the  edges,  as 
there  would  be  a  chance  of  contamination  of  the  bath.  In 
practice  I  have  never  yet  found  my  bath  in  the  least  de- 
gree injured.  The  plates  are  placed  on  the  rack,  and  soon 
dry.  The  drop  at  the  lower  corner  should  be  wiped  off. 
It  is  very  important  to  have  no  dust  about  during  drying. 
The  plates  keep  well  in  a  dry  place. 

The  albumen  may  be  poured  back  into  the  funnel,  and, 
after  re-filtration,  rather  improves.  For  large  plates  the 
time  saved  is  very  great,  and  there  can  be  no  doubt  as  to 
the  perfect  cleanness  of  the  plate.  I  had  by  me  a  large 
quantity  of  glass  which,  from  some  peculiarity,  was  not 
fit  for  use,  from  its  being  found  impossible  to  give  it  a  per- 
fect polish  ;  the  albumen  has  enabled  me  to  use  it  with 
complete  satisfaction. 

Old  plates  are  often  difficult  to  clean,  and  unsatisfactory 
after  all ;  this  plan  will  utilize  them,  and  give  pictures  as 
clean  as  on  new  glasses. 

Just  a  word  of  caution  in  conclusion.  Do  not  be 
tempted  to  use  gum  arabic  for  this  purpose  in  lieu  of 
albumen,  as  it  is  brittle,  and  possessing  a  different  •  con- 
tractile and  expansive  power  to  the  glass,  will  split  the 
film.  Do  not  use,  either,  the  solution  of  india-rubber,  for 
well-known  reasons.  Albumen  is  the  right  thing  and  will 
be  found  very  valuable. 

CHROMO-PHOTOGRAPHY,  OR  PHOTO-MINIATURE. 
BY  A.  DE  CONSTANT. 

Under  this  name  a  process  has  for  several  months  past  been 
practiced  in  Paris.  It  consists  in  cementing  photographs 
upon  glass  possessing  a  slight  convex  surface,  and  in  render- 
ing the  picture  transparent  by  treatment  with  a  certain  de- 
scription of  varnish.  A  photograph  is  slightly  colored  at 
the  back,  and  placed  accurately  upon  another  similar  pho- 
tograph painted  with  less  care,  and  mounted  upon  a  card 
of  the  same  size  as  the  glass.  In  this  way  the  transparency 
of  the  print  attached  to  the  glass  allows  the  picture  under- 
neath to  be  seen  and  to  become  blended  with  th  e  upper 


516 


CHR0M0-PH0T0GRAPHY  OR  PHOTO-MINIATURE. 


one,  whereby  an  effect  of  relief  and  of  remarkable  depth 
is  secured,  while  the  convex  surface  of  the  glass  imparts  a 
softness  similar  to  that  possessed  by  a  charming  miniature 
painting.  The  photographic  production  may  be  said  even 
to  surpass  a  painting  in  effect,  as  in  the  former  no  trace  of 
a  brush  is  to  be  detected. 

I  remember,  some  time  ago,  an  effort  was  made  to  render 
lithographs  transparent,  and  to  color  them  at  the  back, 
with  the  intention  of  thus  producing  a  substitute  for  oil 
paintings,  but  the  result  was  an  ugly  parody;  whereas 
chromo-photographs  (although  based  upon  the  same  mode 
of  production)  leave  nothing  to  be  desired  when  executed 
with  taste. 

It  is  a  matter  for  surprise  that  in  England,  where  water 
color  painting  is  so  much  cultivated,  that  this  process  has 
not  been  successfully  practiced;  and,  moreover,  that  in 
none  of  the  photographic  publications  mention  has  been 
made  of  it.  The  method  has  for  a  long  time  been  appre- 
ciated in  Faris,  and  is  now  being  adopted  in  Germany, 
where  a  work  on  the  subject  has  just  been  published,  by 
Gustav  Meyer,  of  Friburg  (Brisgau).  I  do  not  know  any- 
thing of  the  formula  therein  recommended,  but  the  pro- 
cess generally  employed  in  Faris  appears  to  me  to  present 
certain  difficulties  which  I  will  indicate  for  the  informa- 
tion of  those  who  may  feel  tempted  to  make  a  few  experi- 
ments in  this  branch  of  the  art;  communicating,  at  the 
same  time,  my  own  manner  of  working,  by  means  of  which 
the  freshness  and  purity  of  the  prints  is  not  interfered 
with. 

According  to  the  Paris  mode  of  working,  the  trans- 
parency of  the  prints  is  brought  about  at  the  same  time  as 
it  is  cemented  to  the  glass.  The  photograph  is  cut  of  the 
same  size  as  the  oval  glass  plate,  and  placed  for  a  few 
moments  in  a  mixture  of — 

Canada  balsam  70  parts. 

Gum  mastic  15  " 

Spermaceti  15  " 

heated  in  a  water  bath.  The  print  is  then  applied,  face 
downwards,  to  the  glass,  and  pressed  well  with  the  fingers, 
so  that  it  adheres  perfsctly  over  the  whole  surface,  the 
superfluous  solution  being  pressed  out  from  the  centre  to 
the  margin.  This  solution  is  very  resinous,  and  clings  so 
tenaciously  to  the  fingers  that  the  use  of  essence  of  tur- 
pentine is  necessary  to  remove  it,  thus  rendering  the  work 


CHROMO-PHOTOGRAPHY  OR  PHOTO-MINIATURE. 


517 


both  difficult  and  dirty  in  its  character.  Moreover,  the  solu- 
tion appears  to  me,  after  a  short  time,  to  assume  a  yellowish 
tint,  which  interferes  much  with  the  pure  tones  and  fresh- 
ness of  the  photograph.  To  remedy  these  defects  I  con- 
ceived the  idea  of  rendering  the  photograph  in  the  first 
place  transparent,  and  afterwards  cementing  it  to  the  glass 
in  a  second  operation. 

To  render  the  Print  Transparent. 

The  portrait,  printed  vigorously  upon  a  fine  albume- 
nized  paper  free  from  defects,  is  cut  of  the  size  of  the 
glass,  and  plunged  in  a  mixture  of — 

Paraffine   3  parts. 

Virgin  Wax  1  part, 

Fine  olive  oil .      .      .      .      ,      .      .      1  " 

This  mixture  is  maintained  in  a  liquid  state  in  a  water 
bath,  and  after  the  lapse  of  four  or  five  minutes  the  print 
is  taken  out,  drained,  and  placed  between  sheets  of  filter 
paper,  and  ironed  in  the  same  manner  as  a  wraxed  paper 
negative.  Prints  prepared  in  this  manner  are  perfectly 
transparent,  and,  when  dry,  may  be  placed  in  a  portfolio. 

The  Cementing  Material 
I  prepare  according  to  the  following  formula: — 

Virgin  wax  1  ounce. 

Gum  dammar   23  grains. 

Gum  elemi   23  " 

Oil  of  lavender   10  cent.  cub. 

This  is  dissolved  in  a  bottle  placed  in  hot  water,  and, 
when  well  mixed,  applied  by  means  of  a  piece  of  flannel 
to  the  albumenized  surface  of  the  print.  A  small  quantity 
of  the  same  material  is  heated  in  one  of  the  convex  glasses, 
and  so  manipulated  that  the  surface  is  covered  with  an 
even  film  of  it.  The  print  is  then,  placed,  face  downwards, 
upon  the  glass  surface  in  such  a  manner  that  the  adhes- 
ion is  in  the  first  instance  effected  in  the  hollow  portion  of 
the  plate.  Then,  with  the  end  of  the  fingers,  the  excess 
of  solution  is  pressed  outwards,  care  being  taken  to  allow 
the  glass  to  cool  somewhat,  in  order  that  the  print  may 
not  shift  from  its  proper  position;  at  the  same  time  the 
cooling  should  not  proceed  too  far,  otherwise  it  will  be 
impossible  to  press  out  the  superfluous  wax,  which  militates 
against  the  production  of  a  perfect  result.  This  operation 
demands,  indeed,  a  certain  amount  of  dexterity,  upon 


518 


APPARATUS  FOR  ENLARGEMENTS. 


"which  depends  the  beauty  of  the  picture  and  the  absence 
of  air-bubbles  between  the  glass  and  the  photograph.  The 
upper  face  of  the  glass  is  next  cleaned  (the  convex  surface) 
with  oil  of  lavender,  and  after  a  short  time,  the  cement 
being  cold  and  set,  the  picture  is  ready  for  coloring. 

The  second  picture,  of  which  mention  was  made  at  the 
beginning,  is  prepared  upon  plain  salted  paper,  and  print- 
ed of  the  same  degree  of  vigor  as  the  first.  In  the  second 
print  the  ground  must  be  as  white  as  possible.  It  may  be 
mounted  upon  stout  cardboard,  or  upon  a  second  glass 
fitting  exactly  into  the  other,  according  as  it  is  found  that 
a  greater  or  less  distance  between  the  two  images  pro- 
duces the  best  effect.  In  any  case  it  is  necessary  that  the 
second  glass,  or  the  cardboard  bearing  the  second  print, 
should  be  fixed  in  such  a  manner  that  the  two  photographs 
are  exactly  superimposed. 

I  come  now  to  the  painting,  which  is  executed  in  water 
colors,  those  portions  of  the  dress  such  as  lace,  embroidery, 
ornaments,  &a,  being  treated  with  body  color,  or  gold 
and  silver.  There  are  two  methods  of  coloring:  by  paint- 
ing very  lightly  on  the  back  of  the  transparent  image, 
indicating  the  principal  tints,  and  giving  detail  only  in 
the  hair,  eyes,  and  ornaments;  or  by  coloring  the  print 
more  elaborately,  as  in  the  ordinary  manner  of  painting. 
As  to  the  second  print,  it  may  be  colored  more  coarsely  in 
brilliant,  vigorous  colours,  which,  however,  must  be  sub- 
dued in  the  vicinity  of  the  face.  It  is  necessary  to  place 
one  photograph  upon  the  other  occasionally,  during  the 
operation  of  coloring,  to  judge  of  the  effect. 

I  believe  that  the  more  complete  coloring  of  the  trans- 
parent print,  although  an  operation  of  longer  duration, 
yields  a  better  imitation  of  an  oil  painting,  and  is 
softer  in  the  flesh  tints.  But  all  this  is  a  mat- 
ter of  taste  for  the  t  artist,  whom  a  modest  pho- 
tographer like  myself  must  not  pretend  to  advise.  My 
object  here  is  merely  to  indicate  a  simple  and  easy  manner 
of  practising  this  interesting  method,  in  which  the  painter 
and  photographer  will  for  a  moment  forget  their  rivalry, 
by  working  amicably  together. 

APPARATUS  FOR  ENLARGEMENTS. 
BY  W.  H.  DAVIES. 

Among  the  many  methods  for  the  enlargement  of  our 
small  sized  pictures — such  as  the  solar  camera  with  sun 


APPARATUS  FOR  ENLARGEMENTS. 


519 


and  daylight,  or  the  simple  elongated  copying  camera,  &c, 
as  well  as  by  the  artificial  lights  of  the  lime,  electric,  and 
magnesium  lanterns — there  are,  doubtless,  many  ingenious 
adjuncts  to  the  practice  which  have  either  remained  un- 
published, or  have  not  received  sufficient  publicity.  This, 
I  think,  is  one  of  them. 

I  was  pressed  by  a  friend,  a  short  time  ago,  to  devise  a 
mode  of  enlargement  which  should  be  at  once  the  cheap- 
est, simplest,  and  most  completely  effective  for  all  pur- 
poses, either  of  positive  or  negative  work,  for  either  large 
or  small  sizes.  After  some  cogitation,  I  fixed  on  the  fol- 
lowing plan ;  and  as  every  little  advance  in  the  construc- 
tion of  apparatus  is  worth  recording,  if  it  be  an  advance, 
I  have  "made  a  note"  of  this,  which,  although  it  is 
perhaps  the  oldest  in  principal,  is  yet  so  perfectly  efficient 
that  it  ought  to  be  better  known  than  it  is,  and  more  ex- 
tensively used  than  it  has  ever  yet  been. 

An  empty  room,  fully  sixteen  feet  long,  was  chosen, 
with  a  window  having  a  clear  skyward  exposure  to  the 
north.  The  shutters  of  this  window  were  made  to  close 
properly,  and  the  joints  rendered  light-tight  by  fixing 
cloth,  hinge-fashion,  wherever  it  was  needed.  This  con- 
verted the  room  into  a  earner a-obscur a — a  dark  chamber. 
The  next  operation  was  to  arrange  the  plate-holder  and 
lens,  which  was  done  in  this  way :  a  bellows-camera,  which 
was  capable  of  focussing  with  any  lens  in  stock,  from  the 
shortest  to  the  longest,  was  chosen,  the  base-board  was 
unscrewed,  and  the  camera  reversed  in  position,  the  part 
holding  the  dark  slide  being  now  fixed  to  the  base-board, 
and  the  front  portion  carrying  the  lens  being  made  mov- 
able and  capable  of  being  fixed  at  any  distance  from  the 
plate-holder  by  the  clamping  screw  (a  screw  arrangement 
would  have  been  better  but  it  was  not  at  hand).  This 
camera  was  fitted  with  a  double  sliding  front,  to  move 
horizontally  and  vertically,  together  with  adaptors  for 
every  lens  that  could  be  used  wTith  it.  The  dark  slide  was 
put  aside  as  being  of  no  use,  and  the  focussing  glass  frame 
chosen  as  the  holder,"  and  was  fitted  with  carriers  to  hold 
the  various  sized  positives  and  negatives.  The  altered 
camera  was  fitted  on  a  sloping  board,  adjusted  and  fixed 
at  the  proper  angle  to  the  window  shutter,  from  which  a 
piece  had  been  cut,  (and  which  was  hinged  to  move  back 
out  of  the  way}  the  size  of  the  holder,  and  the  sloping 
space  between  the  camera  and  the  opening  filled  up. 
That  part  of  the  arrangement  was  now  complete,  as  all 


520 


APPAKATUS  FOR  ENLARGEMENTS. 


the  light  which  could  pass  into  the  room  must  now  pass 
through  the  negative  or  positive,  and  then  through  the 
small  camera  and  lens  behind  it. 

All  that  was  wanted  now  was  an  arrangement  to  receive 
the  magnified  image,  and  this  was  simply  managed.  A 
stout  easel  was  made  with  parallel  slides  and  sliding  plate 
carrier,  and  a  triangular  or  T  frame  for  the  bottom  of  it, 
to  which  the  three  legs  were  made  fast  at  the  same  angle 
as  the  camera.  Attached  to  the  T,  base  of  the  easel,  were 
three  grooved  wheels  made  from  two-inch  pulleys  (not 
castors) ;  as  many  beads  to  fit  the  grooves  were  made,  and 
fitted  to  the  floor  like  rails  at  the  proper  distance  and 
position,  and  on  these  the  grooved  pulley  wheels  ran  as 
smoothly  as  possible,  perfectly  parallel  to  the  lens  (the 
planes  being  coincident),  and  capable  of  being  moved 
quite  close  to  the  lens,  or  any  distance  from  that  to  the 
further  end  of  the  room,  sixteen  feet  away;  thus  giving 
any  scale  of  enlargement,  by  using  any  size  of  either  lens, 
transparency  or  negative.  The  arrangement  of  the  focus- 
sing and  the  centering  of  the  image  is  by  the  double  mo- 
tion of  the  lens  in  the  camera  front,  and  an  up  and  down 
motion  of  a  frame,  with  a  ledge  and  catch,  for  glass  or 
paper  fixed  to  the  easel.  By  getting  behind  the  easel  and 
focussing  through,  either  on  a  ground  glass  well  rubbed 
with  chalk,  or  direct  on  the  collodionized  plate,  the  utmost 
possible  sharpness  is  obtainable. 

The  focussing  on  the  ground  glass  is  easy  enough,  but 
the  method  on  the  sensitized  plate  is  not  so,  and  is  effected 
in  this  way  :  A  cap  is  made  for  the  lens  with  yellow  glass 
inserted  in  front,  instead  of  the  opaque  brass  or  leather 
which  is  usual,  and  through  the  yellow  glass,  which  must 
be  a  choice  bit,  free  from  specks  or  striae,  the  image  is  pro- 
jected. "When  all  is  ready,  and  the  focussing  quite  correct, 
the  cap  is  removed  and  the  exposure  proceeds. 

There  are  several  advantages  gained  by  this  mode  of 
working,  and  among  others  this  may  be  mentioned  in 
reference  to  the  Sarony  transparencies.  By  interposing 
an  opaque  card  with  a  suitable  opening,  and  keeping  it  in 
motion  between  the  lens  and  sensitive  plate,  the  vignet- 
ting can  be  carried  to  any  extent  or  made  to  any  shape, 
besides  the  pleasure  of  seeing  what  you  are  doing.  If  the 
room  also  contains  a  water  pipe  and  sink  it  becomes  at 
once  operating  room  and  camera,  and  is  as  near  an  ap- 
proach to  perfection  as  can  be  expected  in  this  sublunary 


PHOTOGRAPHING  MACHINERY. 


521 


sphere,  and,  as  I  said  to  begin  with,  the  cost  is  a  mere 
trifle. 

The  only  method  of  enlargement  I  know  of,  for  which  it 
is  not  fitted,  is  printing  from  a  small  negative  by  direct 
sunlight  on  sensitive  paper  without  development,  and  in 
England  this  method  has  never  enjoyed  much  popularity; 
but  for  all  other,  either  positive  or  negative,  it  is  well 
fitted,  and  certainly  worth  attention. 

PHOTOGRAPHING  MACHINERY. — BY  H.  BADEN  PRITCHARD. 

The  depiction  of  machinery  by  means  of  the  camera  is  a 
task  not  unattended  with  difficulty.  This  is,  in  the  main, 
due  to  two  reasons :  In  the  first  place,  the  lighting  up  of  the 
object  is  generally  very  defective;  and,  secondly,  the  bear- 
ings and  more  important  parts  of  the  machine  are  so  bright 
and  polished  that  the  light  is  reflected  therefrom  in 
patches,  and  forms  upon  the  negative  white  irregular 
blotches. 

If  a  machine  is  situated  in  a  dark  corner  of  a  dark  work- 
shop— as,  indeed,  machinery  generally  is,  the  difficulty  of 
reproducing  the  same  in  the  camera  becomes  greater  still, 
for  when  the  employment  of  artificial  or  reflected  light  is 
rendered  necessary,  the  portions  of  machinery  which  pre- 
sent a  bright  surface  are  even  more  troublesome  to  deal 
with,  from  the  fact  that  they  reflect  an  increased  quantity 
of  light,  while  the  darker  parts  of  the  machine,  situated  in 
the  recesses,  are  not  illuminated  to  any  perceptible 
degree. 

A  great  deal  may  be  done  by  diffusing  the  light  as  much 
as  possible,  by  the  employment  of  white  sheets,  white 
boards  and  the  like,  but  the  real  source  of  the  difficulty 
lies  in  the  nature  of  the  object  to  be  photographed. 

In  a  recent  article  by  Dr.  Vogel  on  the  employment  of 
reflected  light,  that  gentleman  recommends  the  use  of  a 
mirror,  which  must  be  kept  moving  during  exposure  in 
such  a  manner  that  the  darker  and  more  essential  por- 
tions of  the  machine  are  more  frequently,  and  for  a  longer 
period,  illuminated  than  others.  This  mode  of  operating 
is  doubtless  a  very  good  one,  and  very  feasible  when  a 
sufficient  source  of  light  is  at  hand,  but  when  the  latter  is 
weak  and  diffused,  the  plan  would,  I  think,  scarcely  be 
practicable. 

According  to  my  own  experience,  the  best  method  is  to 
apply  a  suitable  coloring  matter  of  a  light  neutral  tint  to 


522 


PHOTOGRAPHING  MACHINEEY. 


all  those  portions  of  the  machine  exhibiting  a  bright  sur- 
face, or,  indeed,  anywhere  where  the  metal  is  not  other- 
wise painted  or  lacquered.  The  mixture  or  paint  I  em- 
ploy is  very  suitable  for  the  purpose,  from  the  fact  that  it 
is  easily  applied,  readily  dried,  and  is  afterwards  rapidly 
and  completely  cleaned  off  by  the  application  of  a  little 
cotton  waste  moistened  with  turpentine.  It  is  thus  com- 
posed : 

Dry  white  lead  5  pounds. 


The  amount  of  lampblack  is  varied  according  to  the 
depth  of  tint  required,  but  on  no  account  must  the  pro- 
portion of  gold  size  be  augmented,  as  otherwise  the  paint, 
when  dry,  is  not  so  easy  of  removal. 

The  advantages  of  applying  a  colored  matter  of  this  de- 
scription to  machinery  about  to  be  photographed  are  very 
evident  ;  the  glaring  points  are  obviated,  the  more  intri- 
cate and  darker  parts  are  lighted  up  effectually,  and 
extreme  contrasts  being  avoided,  a  more  harmonious  pic- 
ture is  the  result,  requiring  for  its  production  a  much  less 
prolonged  exposure  than  would  otherwise  have  been 
necessary. 


Lampblack, 
Gold  size, 
Turpentine, 


3  to  5  ounces. 

.    1  pint. 
•    .  1£  pints. 


CHAPTER  LX. 


HOW  TO  MAKE  RIPE  COLLODION  AT  ONCE — STIPPLING  GLASS  IN 
STUDIO — PRINTING  ON  WOOD  BLOCKS — THE  CALOTYPE  PROCESS. 

HOW  TO  MAKE  RIPE  COLLODION  AT  ONCE.     BY  ALFRED  HUGHES. 

It  is  very  generally  known,  I  believe,  that  if  ether  be 
left  in  contact  with  the  atmosphere  through  the  bottle- 
stopper  flying  out,  or  from  other  causes,  the  ether  becomes 
practically  unfit  for  photographic  use.  The  collodion 
made  from  it  becoming  intensely  red,  gives  thin,  hard, 
wiry  images,  all  roundness,  richness  and  bloom  being 
lost. 

Some  little  time  ago  I  had  some  ether  (a  Winchester 
quart  full),  the  bottle-stopper  of  which  had  been  out  from 
Saturday  till  Monday. 

At  that  time  I  was  experimenting  with  iodides  and 
bromides,  and  accidentally  found  out  the  following  way  of 
using  up  acidified  ether  : 

With  the  ether  above  described  I  made  collodion,  and, 
taking  twenty  ounces,  iodized  it  as  follows  : 

^grains  £per  ounce. 

The  collodion  immediately  turned  a  deep  brown,  and 
remained  so,  giving  hard  images,  and  having  the  appear- 
ance of  a  very  old  sample. 

Twenty  ounces  more  plain  collodion  were  taken,  and 
iodized  as  follows  : 

Iodide  Cadmium,  4  grains. 

Bromide  Cadmium,  2  ** 

This  collodion  remained  quite  colorless.  Knowing  that 
if  this  had  been  made  with  pure  ether,  about  ten  or 
twelve  months'  rest  would  have  been  needed  for  it  to 


Iodide  ammonium,  . 
Bromide  ammonium, 


524 


STIPPLING  GLASS  IN  STUDIO. 


ripen,  and  thinking  that  the  acid  in  the  exposed  ether 
might  need  the  effect  of  time,  I  allowed  the  collodion  two 
days'  rest,  and  tried  it.  It  fogged  slightly.  It  was  put 
aside  again.  In  ten  days  it  was  clean,  gave  beautiful 
negatives  (better  than  those  produced  by  a  similarly 
iodized  collodion  made  of  pure  ether),  and  kept  for  nine 
months. 

Wishing  to  test  this  result  a  little  more,  I  made  another 
collodion,  iodized  as  follows  : 

Iodide  ammonium,   .4  grains. 

Bromide  Cadmium,   2  " 

I  mixed  the  bases  as  above,  so  as  to  get  by  the  ammonium 
a  collodion  to  work  on  the  instant,  and  by  the  cadmium, 
one  that  would  also  keep. 

The  collodion  was  tried  at  once.  It  worked  exceedingly 
well,  but  in  about  a  week  it  became  hard,  slow,  and  as 
useless  as  that  which  was  made  with  ammonium  alone. 

So  I  concluded  that  to  use  acidified  ether,  cadmium 
salts  alone  must  be  used;  and  that  for  ammonium  salts, 
the  greatest  care  must  be  taken  to  have  the  ether  as  pure 
as  possible. 

I  have  written  the  above  simply  as  a  note  of  experience, 
there  being,  I  think,  only  one  practical  result ;  that  is,  a 
hint  how  to  rapidly  make  a  ripe  cadmium  collodion. 

STIPPLING  GLASS  IN  STUDIO.  BY  B.  J.  EDWAKDS: 

In  order  to  produce  the  best  result  in  photographic 
portraiture,  it  is  frequently  found  necessary  to  soften  or 
diffuse  the  light  as  it  enters  the  studio  or  glass  room. 
This  has  usually  been  effected  by  a  system  of  white  blinds 
or  screens  covered  with  tracing-linen.  Another  plan, 
which  has  been  successfully  adopted  by  some  of  the  best 
continental  and  English  photographers,  is  to  stipple  or 
partially  obscure  the  glass  in  the  roof  and  side  of  the 
studio. 

This  plan  I  consider  far  preferable  to  the  use  of  white 
calico  blinds.  It  is  difficult  to  obtain  the  latter  sufficiently 
thin  and  transparent,  and  they  very  soon  become  discol- 
ored, and  render  a  prolonged  exposure  necessary.  On 
the  other  hand,  if  the  glass  be  properly  stippled  to  the 
required  extent,  the  light  may  be  modified  to  any  degree 
without  increasing  the  exposure;  while,  in  many  instances, 


STIPPLING  GLASS  IN  STUDIO. 


525 


a  great  increase  in  rapidity  is  the  result.  This  is  especially 
the  case  where  the  direct  light  from  the  sky  is  obstructed 
in  trees  or  buildings  outside  the  studio. 

As  regards  the  material  best  adapted  for  stippling  the 
glass.  I  have  made  many  experiments  in  this  direction, 
and  now  give  the  formula  for  a  varnish  which  I  have  found 
to  answer  the  purpose  in  every  way.  It  will  not  change 
color,  crack,  or  peel  off ;  can  be  washed  with  cold  water 
without  injury  ;  and,  if  required,  can  be  easily  removed 
and  renewed. 

To  make  the  varnish,  take  one  tube  of  best  flake-white, 
and  one  tube  of  prepared  sugar  of  lead,  as  sold  by  artists' 
colormen.  Empty  the  tubes  into  a  jar,  and  add  one  ounce 
(by  measure)  of  good  mastic  varnish,  and- from  two  to 
three  ounces  of  spirits  of  turpentine.  When  mixed,  the 
varnish  should  be  about  the  consistency  of  new  milk  ;  if 
too  thick,  add  more  turpentine,  taking  care  to  keep  the  right 
proportion  of  mastic  varnish  to  give  body  to  the  mixture. 
This  may  be  ascertained  by  pouring  a  little  of  the  compo- 
sition on  to  a  glass  plate  ;  if  too  thin,  it  will  run  in  streaks, 
and  a  little  more  mastic  varnish  must  be  added,  but  only 
sufficient ;  if  too  much  be  used  it  will  become  sticky  and 
unmanageable  in  working. 

To  stipple  the  glass,  make  a  pad  or  a  dabber  of  a  large 
tuft  of  cotton  wool  covered  with  fine  cambric  or  muslin  ; 
then,  with  a  brush,  rapidly  paint  over  one  square  of  the 
glass  to  be  stippled,  and  immediately  dab  it  all  over  with 
the  pad.  This  must  be  done  quickly,  and  before  the  var- 
nish has  had  time  to  act.  It  is  better  to  finish  at  once, 
and  not  attempt  to  go  twice  over  the  same  place,  or  the 
work  will  appear  patchy  when  dry.  If  properly  managed 
it  will  have  the  appearance  of  very  fine  ground  glass  by 
transmitted  light. 

The  tint  may  be  altered,  if  desired,  by  the  addition  Ox 
a  little  Prussian  blue  or  indigo  to  the  flakd  white  when 
mixed. 

If,  at  any  time,  it  should  be  desired  to  remove  the  varnish, 
this  may  easily  be  done  with  a  solution  of  common  wash- 
ing soda  in  warm  water  ;  and  the  glass,  after  well  rinsing 
with  cold  water,  may  be  again  coated  with  the  composi- 
tion. 


526 


PKINTING  ON  WOOD  BLOCKS. 


BY  W.  T.  BOVEY. 

A  gentleman,  who  is  intimately  acquainted  with  the  art 
of  wood  engraving  in  all  its  details,  once  remarked  to  me, 
that  a  certain  fortune  awaited  the  individual  who  could 
succeed  in  producing  a  sharp  photographic  image  on  the 
surface  of  a  wood  block.  In  reply,  I  pointed  out  the  dis- 
similarity between  a  photograph  from  nature,  and  a  pencil 
sketch  drawn  by  the  hand  of  a  "  wood  draughtsman/'  and 
inquired  whether  the  difficulty  would  be  surmountable. 
"  Yes,  certainly,"  was  the  response  ;  "  that  is  to  say,  if  the 
photograph  could  be  produced  with  a  material  similar  to 
that  usually  employed  as  a  facing  on  which  the  pencil 
drawings  are  made."  A  few  days  only  had  elapsed  subse- 
quent to  the  holding  of  the  conversation  above  briefly 
alluded  to,  when  the  process,  with  every  condition  fulfilled, 
was  mine.  The  fortune,  however,  is  as  far  off  as  ever — 
possibly  because  process-making  is  more  my  peculiar/brfc 
than  skill  in  fortune-getting.  Such  being  my  weakness,  I 
am  content  to  yield  up  freely  all  chances  of  pecuniary 
benefits,  together  with  exhaustive  details  of  my  process, 
which  directions  will,  I  think,  enable  any  photographer  to 
succeed  in  producing  the  picture,  if  not  the  promised  for- 
tune. 

First.  Procure  the  finest  quality  white  of  zinc  (dry). 

Second,  mix  to  saturation  chloride  of  ammonium,  or 
other  chloride  salt,  with  water. 

Next,  take  the  requisite  quantity  of  white  of  zinc,  and 
triturate  to  a  fine  powder  on  a  slab  or  in  a  mortar  ;  then 
add  sufficient  of  the  chlorodized  solution  to  the  powder  to 
form  a  thick  paste,  which  should  then  be  ground  to  a  de- 
gree of  fineness  equal  to  butter.  The  paste  must  be 
thinned  with  albumen  diluted  slightly  with  the  chloride 
solution  (the  albumen  must  be  well  beaten  before  used), 
and  the  pigment  is  ready  for  immediate  use. 

To  coat  the  block,  a  flat,  soft  hair  brush  is  most  suitable. 
The  pigment  should  be  laid  on  in  a  thin  and  even  coating, 
and  the  brush  marks  removed  with  a  grainer's  badger. 
The  block  may  be  set  aside  in  a  warm  place  to  dry.  When 
thoroughly  dried,  proceed  to  sensitize  in  the  following 
described  way  : — Dip  a  soft  hair  brush  into  a  silver  solu- 
tion (the  ordinary  printing  bath  will  answer  the  purpose 
thoroughly),  and,  whilst  the  brush  is  full  of  liquid,  brush 
over  the  surface  of  the  block  very  lightly.    This  operation 


THE  CALOTYPE  PROCESS. 


527 


effectually  prevents  the  forming  of  air-bubbles  and  streaks 
when  the  prepared  surface  is  brought  into  contact  with 
the  silver  bath. 

To  bring  the  face  of  the  block  into  contact  with  the 
silver  bath,  commence  at  one  of  the  side  edges  of  the  wood, 
and  bring  the  block  gently  down  until  the  whole  surface 
is  resting  on  the  bath  solution.  Hold  the  block  in  such  a 
position  as  will  prevent  any  part  but  the  surface  from  con- 
tact with  the  sensitizing  fluid.  From  three  to  five  minutes 
will  suffice  to  render  the  preparation  sensitive.  On  re- 
moval from  the  bath,  place  the  block  on  edge  on  a  few 
thicknesses  of  blotting-paper  to  drain  and  dry.  When  dry, 
the  block  is  ready  for  printing,  which  operation  may  be 
executed  in  a  suitable  printing  frame,  or  the  negative  may 
be  held  to  the  sensitive  surface  firmly  with  the  fingers 
whilst  the  printing  is  going  on.  The  printing  moves 
rapidly,  so  that  patience  is  not  severely  taxed.  When  the 
primitive  mode  of  working  is  resorted  to,  register  marks 
applied  to  the  edges  of  the  negative  in  India  ink  afford 
valuable  aid  in  readjusting  the  negative,  in  the  event  of 
its  being  moved  before  the  print  has  attained  sufficient 
depth. 

Print  but  little  deeper  than  the  depth  required  in  the 
finished  picture,  which,  when  complete,  is  produced  in  a 
thin  layer  of  pigment  that  will  not  wash  off ;  and  I  am 
persuaded  that  the  pressure  of  the  graving  tool  would  not 
cause  the  color  to  "  chip." 

The  print  need  not  be  toned.  Fix  in  hypo  :  hypo,  four 
ounces  ;  water,  one  pint.  Wash  thoroughly  under  a  tap, 
and  dry. 

The  work,  as  far  as  the  photographer  is  concerned,  is 
then  completed.  A  little  scraping  with  a  piece  of  glass 
will  remove  the  stains  on  the  edges  of  the  block ;  these, 
however,  are  not  injurious  if  left  alone,  but  their  presence 
does  not  denote  a  neat  finish. 


THE  CALOTYPE  PROCESS — BY  COL.  A.  G.  GREENLAW. 

First  examine  and  select  thin  negative  paper,  and  reject 
all  that  show  any  irregularities,  holes,  patches  of  unequal 
density,  &c. 


528 


THE  CALOTYPE  PROCESS. 


Iodize. 


Make  a  solution  of — 


Iodide  of  potassium  . 
Bromide  of  potassium 


1,000  grains. 
300  grains. 


(For  much  foliage  the  latter  may  be  increased  to  450  grains.) 
Distilled  water  40  ounces, 

and  add  enough  of  pure  iodine  to  give  the  solution  a  dark 
claret  color.    Then  filter. 

Into  this  place  as  many  sheets  of  paper  as  you  can  do 
easily,  being  careful  that  no  air-bubbles  exist.  Allow  the 
papers  so  immersed  to  rest  for  one  hour  ;  then  turn  the 
whole  upside  down,  and  hang  the  sheets  up  to  dry,  taking 
off  the  last  drops  with  white  blotting-paper.  This  may 
be  done  in  diffused  light.  "When  dry,  place  sheet  over 
sheet  evenly  in  a  portfolio  in  which  no  other  papers,  except 
blotting-paper,  are  placed.  They  are  then  iodized  a  dark 
purple,  which  will  keep  any  time.  They,  however,  turn  a 
light  brown  color.  Be  sure,  in  working,  that  nothing 
touches  the  paper,  for  the  very  slightest  touch  is  sure  to 
cause  a  stain  in  the  development. 


Now  float  a  sheet  of  your  iodized  paper  on  this  (smooth 
side  downwards)  until  the  purple  has  turned  an  uniform 
yellow,  which  is  iodide  of  silver.  Allow  it  to  rest  for  one 
minute  ;  after  this,  remove  and  immerse  in  distilled  water, 
where  it  should  remain  for  two  or  three  minutes  ;  if  to  be 
kept  for  some  time,  remove  to  another  dish  of  distilled 
water.  Place  now  on  clean  white  blotting-paper,  face  up- 
ward, and  remove  by  blotting-paper  all  moisture  from  the 
surface  (these  sheets  can  be  again  used  for  ironing  out  the 
wax  by-and-bye)  ;  then  place  between  blotting-paper,  or 
hang  up  to  dry  ;  when  quite  dry,  place  in  your  dark  slides. 


Sensitizing  Solution. 


Nitrate  of  silver  . 
Glacial  acetic  acid 
Distilled  water  . 


2$  ounces. 
.  2£  ounces. 
40  ounces. 


Development. 


Gallic  acid  .  . 
Spirit  of  camphor 
Distilled  water  . 


200  grains. 
.   1  drachm. 
40  ounces. 


THE  CALOTYPE  PROCESS. 


529 


This  is  a  saturated  solution  of  gallic  acid  ;  it  soon  de- 
composes ;  the  spirit  of  camphor  is  added  to  preserve  it. 
When  about  to  develop,  filter,  and  add  to  every  five  ounces 
one  drachm  of  the  following  solution  : — 


Pour  into  your  dish  quickly,  and  immediately  float  the 
picture  side  of  your  paper,  which  is  slightly  visible,  on  it, 
being  very  careful  that  there  be  sufficient  liquid  to  pre- 
vent the  paper  touching  the  bottom  of  the  dish.  Con- 
stantly watch  it  until  the  picture  becomes  visible  on  the 
back,  and  the  paper  has  a  kind  of  brown,  greasy  appear- 
ance. Continue  the  development  until,  in  holding  up  a 
corner  when  the  sky  is  before  the  light,  you  cannot  see 
your  finger  when  moved  about  between  the  light  and  the 
paper.  If  it  is  not  dark  enough  before  the  gallate  of  sil- 
ver decomposes,  you  have  under-exposed.  Decomposed 
gallate  of  silver  ceases  to  develop. 

Do  not,  when  examining  your  paper,  lift  more  than  the 
corner,  as  an  oxide  of  gallate  of  silver  forms  rapidly  on  the 
surface  like  a  crust,  and,  on  replacing  your  picture,  it 
causes  innumerable  marble  appearances  ;  so  also  if  you  do 
not  place  your  paper  speedily  on  the  solution  in  the  first 
instance.  It  may  be  removed  by  drawing  a  sheet  of  blot- 
ting-paper over  the  surface  of  the  solution.  Eemove  to  a 
dish  of  common  water,  and  wash  out  the  brown  tinge 
caused  by  more  or  less  decomposed  gallate  of  silver. 
When  well  washed,  you  may 

Fix  it  by  placing  it  in  a  solution  of  hyposulphite  soda, 
one  and  a-half  ounce  to  one  pint  of  water,  till  every  ves- 
tige of  the  yellow  iodide  of  silver  be  removed,  after  which 
wash  in  eight  or  ten  different  changes  of  water ;  you  have 
then  a  fine,  clear,  and  dense  negative.  To  render  it  suffi- 
ciently transparent  for  printing  you  must  proceed  to 

Wax  it.  This  is  done  as  follows  : — Place  it,  when  dry, 
face  downwards  on  clean  blotting-paper ;  upon  it  put  a 
sheet  of  blotting-paper,  and  pass  a  moderately  hot  iron 
over  it;  this  is  to  ensure  the  picture  being  perfectly  dry  be- 
fore waxing.  Now  remove  the  upper  blotting-paper,  and 
pass  the  iron  over  the  picture,  following  the  iron  with  a 
piece  of  white  wax  until  the  whole  picture  is  saturated  ; 
do  each  picture  thus.    If  travelling,  you  may  wax  all  your 


Nitrate  of  silver 
Glacial  acetic  acid 
Distilled  water  . 


30  grains, 
f  drachm, 
1  ounce. 


630 


THE  CALOTYPE  PKOCESS. 


sheets  together  like  a  block,  with  a  piece  of  clean  blotting- 
paper  waxed  to  the  top,  and  another  to  the  bottom.  To 
print  from  it,  you  need  to  remove  all  the  wax  you  possibly 
can  by  placing  a  sheet  of  old,  used  blotting-paper,  and 
passing  a  hot  iron  over  it,  and  repeating  it  till  not  a  ves- 
tige of  wax  appears  on  the  blotting-paper  (use  red,  as  it 
shows  the  wax  spots  better  than  the  white.) 

I  have  used  this  process  for  years  in  India,  and  find  it 
most  simple.  I  obtained  the  first  prize  for  my  pictures  so 
taken  at  an  exhibition.   With  cleanliness  it  is  certain. 


CHAPTEE  LXI. 


THE  FERROTYPE. 

The  general  treatment  of  the  chemicals,  the  posing,  and 
lighting  are  the  same  in  taking  a  ferrotype  as  in  taking  a 
negative,  and  need  not  be  repeated  under  this  head.  There 
is  one  thing,  however,  that  should  be  done  to  avoid  the  yellow 
appearance  that  ferrotypes  are  apt  to  have,  and  that  is  as 
follows  :  After  having  developed  the  impression  and  washed 
off  the  developer,  flow  the  plate  thoroughly  with  a  strong 
solution  of  gallic  acid,  and  wash  well  again  before  fixing  in 
the  cyanide  of  potassium.  The  best  varnish  for  ferrotypes 
is  Anthony's  Diamond  Varnish,  which  does  not  change  color 
by  the  action  of  light,  as  many  others  do. 

Ferrotypes,  as  ordinarily  made,  are  reversed.  To  remedy 
this  partial  defect  a  reflector  is  used. 
This  is  made  of  a  prism  of  white  glass, 
silvered  on  two  of  its  sides.  The  metal 
frame  in  which  it  is  held  screws  on  the 
front  of  the  tube  and  the  camera,  and 
is  placed  sideways  to  the  sitter. 

Another  mode  of  making  ferrotypes 
with  pure  whites  is  to  redevelop,  be- 
fore fixing,  with  pyrogallic  acid,  acetic 
acid,  and  silver,  exactly  as  in  redevelop- 
ing a  negative. 

Medallion  ferrotypes  are  made  by  in- 
terposing between  the  sitter  and  the 
camera  a  sheet  of  white  card  board,  with 
a  large,  oval  opening.  This  is  supported 
by  a  light  frame  of  wood  in  a  slightly  inclined  position.  The 
background  should  be  of  a  dark  color.  The  effect  of  taking 
a  picture  in  this  way  is  to  produce  an  oval  picture  with  a 
white  border.  Pictures  made  in  this  style  are  especially 
adapted  for  being  embossed  by  means  of  the  cameo  press. 

Vignetted  pictures  are  made  in  the  same  way,  the  differ- 
ence being  in  the  making  the  edge  of  the  opening  in  the  card 
board  serrated,  and  placing  it  quite  out  of  focus.  (See  Fig.  31). 


532 


THE  FERROTYPE. 


Ferrotypes  are  now  usually  mounted  on  ornamented  cards, 
which  are  perforated  or  punched  with  openings  of  varying 
size  and  shape.  The  ferrotype  is  fastened  to  these  by  means 
of  gummed  paper,  and  the  aperture,  being  embossed,  has  an 
indented  border  or  edge  to  receive  the  ferro  plate.  Many  of 
these  cards  have  gilt  or  tinted  lines,  similar 
to  the  ordinary  carte  de  visite,  printed  on 
plain  and  tinted  boards. 

Again,  it  is  very  common  to  place  the  fer- 
rotype in  prettily-designed  paper  cases  or 
envelopes.  (See  illustration,  No.  54).  These 
are  made  of  tinted  papers,  with  oval  and 
arch  openings,  and  of  several  sizes.  They 
are  provided  with  a  flap,  which  protects  the  portrait  from 
injury.  The  carte  envelope  also  forms  a  very  suitable  cover- 
ing to  deliver  the  picture  in,  and  has  generally  the  name  and 
address  of  the  photographer  printed  on  it. 


Open  view  of  Fig.  7. 


CHAPTER  LXII. 


COLLODIONS. 


Fig.  3. 


The  principal  new  feature  in  connection  with  this  article 
is  the  making  of  emulsions,  containing  nitrate  of  silver  and 
bromide  of  silver.  These  emulsions,  which  were  first  success- 
fully used  by  Mr.  Sayce,  have  been  made  a  special  study  by 
Mr.  M.  Carey  Lea,  who  introduced  important 
modifications.  There  was,  however,  a  disad- 
vantage in  their  use,  arising  from  the  fact  that 
it  was  necessary  to  use  the  emulsion  at  just 
the  proper  time  after  making  it,  or  run  great 
risk  of  not  succeeding  in  getting  satisfactory 
pictures. 

Mr.  Lea's  formula  has  been  modified  by  Col. 
Stuart  Wortley,  and  the  result  of  the  combined 
efforts  of  these  gentlemen  is  as  follows  : 


Plain  collodion,  .... 
Pure  anhydrous  bromide  of  cadmium, 
Nitrate  of  uranium, 
Nitrate  of  silver,  .... 


1  ounce. 
7  grains. 
30 

18  " 


Dissolve  one  part  of  nitrate  of  uranium  in  two  parts  of 
ether,  and  let  stand  for  some  hours  ;  the  water  of  crystalliza- 
tion that  is  in  the  uranium  will  fall  to  the  bottom  of  the 
bottle,  leaving  a  top  layer  of  ether  containing  pure  uranium, 
and  it  is  this  top  layer  which  is  used  for  the  emulsion.  It  is 
desirable  that  the  nitrate  of  uranium  should  be  acid  ;  and 
should  it  not  after  solution  in  ether  test  acid,  it  will  be  ad- 
visable to  add  a  minim  or  two  of  acid  per  ounce — nitric 
acid  in  preference. 

The  quality  of  an  emulsion  depends  very  greatly  on  the 
cotton  used  in  making  the  collodion — a  short,  powdery  cotton 
being  best. 

After  the  plate  has  received  its  coating  of  collodion,  it  is 
placed  in  a  dish  of  distilled  water,  and  left  until  all  greasi- 
ness  disappears.  It  is  then  taken  out  and  drained,  and  placed 
for  three  minutes  in  the  preservative.  Mr,  H.  Cooper  makes 
his  preservative  as  follows  : 


534  COLLODIONS. 

Distilled  water,    .   4  ounces. 

White  sugar,   20  grains. 

Gum  Arabic,   60  " 

Gallic  acid,   12  " 


The  plates  are  then  dried  carefully  in  the  dark. 

These  plates  are  said  to  be  as  sensitive  as  the  wet,  being 
developed  by  the 

Fig.  4. 


Alkaline  Development. 

Mr.  M.  C.  Lea  recommends  the  following  mode. 
Make  three  solutions,  viz.  : 

1.  Progallic  acid  in  alcohol,  sixty  grains  to  the  oumce. 

2.  Carbonate  of  ammonia  in  water,  eighty  grains  to  the 
ounce.    To  be  kept  well  corked. 

3.  Bromide  of  potassium  in  water,  sixty  grains  to  the  ounce. 
When  ready  to  develop,  mix  together  in  a  small  vial  half 

an  ounce  of  the  bromide  solution  and  three  quarters  of  an 
ounce  of  the  carbonate  of  ammonia  solution,  and  mix  them  well. 

Then  put  into  a  dish  of  proper  size  four  ounces  of  water,  to 
which  add  half  a  dram  of  the  pyrogallic  acid  solution,  and 
immerse  the  plate  so  as  to  avoid  uneven  wetting. 

Then  take  out  the  plate  and  add  fifteen  or  twenty  drops  of 
the  mixture  of  bromide  and  carbonate,  and  put  the  plate  back 
again  in  the  mixture.  If  the  plate  has  been  properly  exposed, 
it  develops  rapidly.    When  the  details  are  well  worked  out, 


COLLODIONS. 


535 


add  at  once  half  a  dram  of  the  solution  of  carbonate  of  am- 
monia.   This  will  give  the  negative  its  proper  density. 

Fix  in  a  very  weak  hypo  bath,  one  ounce  of  hypo  to  fifty 
of  water. 

Mr.  Lea  advises  the  use  of  water  solutions  at  the  tempera- 
ture of  seventy  or  eighty  Fi 
degrees,  and  in  cases  of 
under  exposure  consider- 
ably warmer.  In  case 
very  warm  water  be  used, 
a  little  more  bromide  of 
potassium  should  be  used 
in  the  developer. 

The  remarks  made  by 
Mr.  Lea  as  to  the  origin 
of  the  use  of  ammonia  in 
connection  with  dry  plate 
photography  are  not  ex- 
actly correct. 

The  first  use  of  ammo- 
nia in  connection  with  a 
negative  was  by  Mr.  H. 
T.  Anthony  —  this  was 
very  long  ago — a  simple,  dry  bromo-iodized  plate  without  pre- 
servative being  exposed  to  the  vapor  of  ammonia  and  pro- 
ducing a  negative  with  an  instantaneous  exposure.  The 
knowledge  of  the  ac- 
tion of  an  alkali  upon 
the  dry  salts  of  sil- 
ver, some  three 
years  after  the  ex- 
periment alluded  to, 
was  the  cause  of  the 
trial  of  its  action  up- 
on the  chloride  of  sil- 
ver i  n  connection 
with  albumen.  The 
first  experiment  in 
this  direction  was  a 
perfect  success. 

Upon  the  intro- 
duction of  the  dry 
tannin  plates,  it  oc- 
curred to  Mr.  An- 
thony that  the  vapor  of  ammonia  might  be  used  with  them 


Fig.  6. 


Secrete/- 


536 


COLLODIONS. 


Closed  view  of  Fig.  7. 


to  advantage.  A  trial  was  made  and  was  perfectly  success- 
ful, an  instantaneous  negative  having  been  made. 

Subsequently  a  society  of  amateurs  was  formed  for  the 
purpose  of  mutual  aid  and  exchange  of  pictures.  Mr.  Borda, 
of  Philadelphia,  was  one  of  the  members.  It  was  suggested 
to  him  by  Mr.  Anthony  to  try  the  ammonia  with  his  tannin 
plates.  Mr.  Borda,  fearing  that  his  plates  would  not  keep 
long  after  fuming,  conceived  the  idea  of  exposing  first  and 
fuming  afterward.  In  carrying  out  this  idea,  he  found  that 
the  picture  was  developed  to  a  certain  extent  by  the  action 

of  the  ammonia.  The  publication 
of  this  fact  induced  other  gentle- 
men to  investigate  the  matter,  and 
thus  has  been  worked  out  the  proc- 
ess of  alkaline  development. 

The  yellow  light  ordinarily  used 
to  illuminate  the  dark  room  in  the 
wet  collodion  process  is  too  strong 
for  the  bromide  emulsion  process. 
A  dark  ruby  red  glass  is  required 
with  the  latter  process  on  account 
of  its  excessive  sensitiveness. 

Pure  distilled  water,  or  water  ob- 
tained by  melting  ice,  should  be 
used  for  making  the  silver  negative 
solution.  Rain  water  should  never 
be  used  unless  it  has  first  been  puri- 
fied by  adding  a  little  nitrate  of  sil- 
ver to  it  and  leaving  it  to  stand  in 
the  sunlight  as  long  as  any  deposit 
takes  place. 

Collodions  for  all  photographic 
uses  are  manufactured  by  us  ;  we  also  keep  a  supply  from 
all  other  makers. 


CHAPTEE  LXIII. 


ORGANIC  DEVELOPERS. 

There  have  been  used  many  developers  compounded  of 
the  ordinary  salt  of  iron  and  different  organic  matters.  One 
of  the  best  of  these  is  made  as  follows  :  Make  a  solution  of 
gelatin,  ten  grains  to  the  ounce  of  water,  and  a  solution  of  tan- 
nin, fifteen  grains  to  the  ounce  of  water.  While  the  gelatin 
solution  is  warm,  add  to  it  three  drops  of  the  tannin  solution, 
and  mix  thoroughly.    Add  one  drop  of  this  mixture  to  each 


Fig.  8. 


ounce  of  the  ordinary  developer.  This  slight  addition  makes 
a  remarkable  difference  in  the  action  of  the  developer,  and 
enables  one  to  use  it  over  and  over  again  merely  by  filtering. 

Instead  of  gelatin,  various  other  organic  matters  can  be 
used  with  the  tannin,  viz.,  starch,  tapioca,  gum  Arabic,  etc. 

Another  excellent  developer  is  compounded  as  follows  : 

Double  sulphate  of  iron  and  ammonia,    ...  4  ounces. 

Rock  candy,   |  ounce. 

Water,   64  ounces. 

Acetic  acid,  No.  8,   4  " 


538 


DEVELOPING. 


An  excellent  developer  for  ferrotypes  is  made  as  follows  : 
Prepare  a  saturated  solution  of  protosulphate  of  iron,  also 
dissolve  two  grains  of  tannin  in  an  ounce  of  alcohol.  Add 
gradually  of  the  tannin  solution  to  that  of  iron  until  the  lat- 
ter ceases  to  redissolve  the  precipitate  formed.  Then  add  a 
Fiff  9  very  little  nitric  acid  to 

redissolve  the  precipitate. 
Dilute  the  solution  by  the 
addition  of  twelve  times  its 
bulk  of  water.  Now,  by 
adding  to  each  ounce  about 
half  the  quantity  of  acetic 
acid  ordinarily  used,  the  de- 
veloper will  be  ready.  This 
developer  gives  fine,  vel- 
vety blacks  and  rich,  pure  whites. 

The  ordinary  developer  for  ferrotypes  can  be  very  much 
improved  by  merely  adding  a  trace  of  tannin  to  it  just  before 
being  used. 

A  defect,  frequently  occurring  in  ferrotypes,  viz.,  a  yellow 
color  after  being  varnished,  can  be  prevented  by  proceeding 
as  follows  :  After  developing  and  washing,  flow  the  plate 
with  a  two-grain  solution  of  gallic  acid.  After  a  short  time 
wash  well  again  and  then  fix 


Developing. 

Photographers  continue  to  use  generally  the  simple  iron 
developer,  ordinarily  obtaining  sufficient  intensity  without 
recourse  to  redeveloping.  The  demand  for  pictures  called 
"  Kenibrandt's,"  has  somewhat  modified  the  character  of  neg- 
atives, a  thin  collodion  and  a 
weak  developer  being  used. 
The  negatives  are  printed  from 
in  the  shade.  As  organic  mat- 
ter added  to  the  developer  in- 
creases the  reducing  action,  it 
is  sometimes  desirable  to  use  it. 

An  excellent  organic  devel- 
oper is  composed  of  protosul- 
phate of  iron  and  gelatin — one  of  the  best  of  these  is  "Miller's 
Intensifying  Iron  Developer."  This  works  best  mixed  in 
small  proportions  with  the  double  sulphate  of  iron  and  am- 


DEVELOPING. 


539 


proper  pro- 
all  the  in- 


rtionia.  The 
portions  of 
gredients  must  be  determ- 
ined by  experience. 

Mr.  H.  J.  Newton's 
latest  formula  is  : 


Fig.  11. 


Protosulphate  of  iron,  1  ounce. 

Sulphate  of  ammonia,  1  " 

Water,  16  ounces. 

To  the  above  solution  add  thirty  drops  of  concentrated  am- 
monia, and  redissolve  the  precipitate  by  adding 

Acetic  acid,  No.  8,  1J  ounces. 

Julius  Krueger's  new  developer  : 

a.  Sulphate  of  iron,  1  ounce. 

Distilled  water,  16  ounces. 

Absolute  alcohol,  J  ounce. 

0.  Morphia,  8  grains. 

Glacial  acetic  acid,  J  grain. 

Distilled  water,  2  grains. 

When  the  developer  is  required  for  use,  a  mixture  is  made 
of  eight  parts  of  solution  a  and  one  part  of  liquid  b  for  the 
weak  developer. 

Ferrotype  developer  : 

Protosulphate  of  iron,   1  ounce. 

Water,   20  ounces. 

Acetic  acid,  No.  8,   2  " 

Sulphate  acid,  CP.,   12  drops. 

Or,  Water,   16  ounces. 

Protosulphate  of  iron,   1  ounce. 

Epsom  salts,   1  " 

Acetic  acid,  No.  8,      .....  1J  ounces. 


CHAPTEE  LXIV. 


PROCESSES  OF  MR.  T.  C.  ROCHE,  THE  CELEBRATED 
PHOTOGRAPHER. 

Negative  Bath, 

Nitrate  silver,  4  ounces. 

Water  distilled,        ....         40  " 

When  the  silver  is  all  dissolved,  add  eight  grains  of  iodide 
of  potassium  dissolved  in  one  ounce  of  water.  Shake  the 
whole  well  up  and  filter.  In  trying  a  plate,  if  there  is  any 
trace  of  fog  (not  from  over  exposure),  add  one  or  two  drops 
of  nitric  acid,  C.  P. 

After  constant  use  the  bath  becomes  saturated  with  excess 
of  iodine,  ether,  alcohol,  and  organic  matter.    When  in  this 

state,  it  is  almost  impossible  to 
Fi&* 12-  get  anything  like  clean  work. 

The  quickest  and  best  remedy  to 
rectify  the  bath  is  Boiling.  For 
a  bath  of  forty  ounces,  pour  one 
pint  of  distilled  water  in  an 
evaporating  dish  $  now  pour  the 
bath  solution  in  and  mix  up  with 
a  glass  rod  ;  then  add  two  or 
three  drops  of  liquid  ammonia 
and  mix  well  up.  Now  test  the 
bath  for  alkalinity  with  red  lit- 
mus paper.  If  it  does  not  turn 
blue,  add  more  ammonia,  one  or 
two  drops,  or  enough  to  show  a 
decided  blue  color  on  red  litmus 
paper. 

Set  the  evaporating  dish  on  a  stove,  or  use  any  other  mode 
of  heating,  so  as  to  bring  the  solution  to  the  boiling  point 
When  the  heat  begins  to  act  on  the  bath,  it  will  turn  pink, 
brown,  dark  brown,  and,  as  it  approaches  the  boiling  point, 
it  will  become  quite  black.  It  is  better  to  let  it  boil  a  little, 
say  five  or  ten  minutes.    When  it  begins  to  boil  it  will  be 


PROCESSES  OF  MR.  T.  C.  ROCHE. 


541 


clear,  and  all  iodides  and  organic  matter  will  be  separated, 
and  the  ether  and  alcohol  will  evaporate.  The  next  opera- 
tion is  to  set  the  bath  away  to  cool, 
and  when  cool  filter  clear  ;  then  test 
for  strength.  If  too  strong,  reduce  with 
distilled  water  ;  if  too  weak,  add  silver 
to  the  proper  strength,  thirty-five  grains 
for  summer  and  forty  grains  for  winter. 
This  bath  is  alkaline,  and  it  is  neces- 
sary to  add,  drop  by  drop,  C.  P.  nitric 
acid  to  it  until  it  shows  an  acid  reac- 
tion with  blue  litmus  paper.  The  bath 
will  not  require  re-iodizing,  and,  as  a 
general  thing,  with  Anthony's  new  negative  collodion,  will 
give  clean,  brilliant  negatives,  full  of  detail  and  free  from 
hardness,  and  work  quickly.  This  mode  of  treating  a  bath 
in  the  studio  or  field  is  quick  and  certain — no  sunning,  no 
making  of  new  solutions  or  waste  of  silver.  It  has  been 
thoroughly  tested  for  the  last  twelve  years. 

The  Developer  for  Field  Work. 


Double  sulphate  of  iron  and  ammonia,     ...  4  ounces. 

Water,   64  " 

Yellow  rock  candy,     .......  |  ounce. 

Acetic  acid,  No.  8,   6  ounces. 

Or, 

Double  sulphate  of  iron  and  ammonia,      .       .  3  ounces. 

Yellow  rock  candy,   |  ounce. 

Miller's  developer,   1  " 

Acetic  acid,   4  ounces. 

Water,   64 


If  the  silver  bath  has  been  in  use  long,  or  is  old,  the  ad- 
dition of  one  or  one  and  a  half  ounces  of  alcohol  to  the  above 
developers  will  cause  the  solution  to  flow  more  freely.  As 
a  general  rule,  these  developing  solutions  reduce  the  time 
for  dark  details  at  least  one-half.  For  studio  work,  this  de- 
veloper is  too  strong,  and  should  be  reduced  with  water  to 
suit  the  light. 

Instructions  for  Field  Work. 

For  field  work,  don't  stint  yourself  in  lenses.  Have  plenty, 
or  at  least  three  pairs  for  stereoscopic .  use.  In  going  but 
a  short  distance  from  your  home,  you  will  require  only  a 
dark  box  or  tent,  with  all  necessary  chemicals,  camera  stand, 


542 


PROCESSES  OF  MR.  T.  C.  ROCHE. 


and  negative  box  ;  but  for  an  extended  trip  you  will  require 
a  chemical  box  or  miniature  stock  depot,  divided  up  into 
square  compartments,  to  pack  your  bottles  and  extra  stock 
in,  as  on  railroads  they  are  handled  rather  roughly.  If  trav- 
eling over  mountains  on  mule  paths,  you  will  require  the 
boxes  made  long  and  narrow,  so  that  they  can  be  packed 
readily  on  each  side  of  the  mule,  and 
can  be  well  tied,  so  that  if  your  mule 
chooses  to  roll  over  he  can  hurt  noth- 
ing. It  is  always  best  to  make  out 
a  careful  list  of  everything  needed, 
for  if  you  wish  to  do  good  work  go 
prepared  for  it,  and  do  not  begin  to 
make  excuses  about  forgetting  this 
or  that  article.  Take  a  pride  in  your 
work,  and  take  all  inconveniences 
you  may  meet  with  in  good  part. 
Keep  your  temper  and  powder  dry.  It  is  better,  if  you  have 
the  time,  to  reconnoitre  the  place  on  some  other  day.  Pick 
out  your  standpoints  ;  look  out  for  what  will  make  good 
stereoscopic  views,  and  what  will  make  good  eight  by  ten  or 
larger  size.  Mark  down  the  time  of  day  the  light  is  most 
suitable.  In  this  way  you  can  start  in  the  morning  with 
your  things,  keeping  the  sun  three-quarters  on  your  work, 
and  follow  him  all  day — except  for  strong  cloud  or  moonlight 
effects  ;  for  these  you  will  require  a  box  with  a  lid  over  the 
lenses,  and  will  have  to  work  directly  toward  the  sun.  Watch 

until  the  sun  is  capped 
on  the  edge  by  a  cloud, 
then  expose  two  or 
three  seconds.  For  the 
clouds,  close  the  lid  half 
down  and  keep  moving 
it  slightly  up  and  down 
between  the  horizon 
and  foreground.  For 
detail  in  the  picture,  as 
a  general  thing,  this 
class  of  views  is  more 
for  cloud  effects  than  a 
picture  full  of  details 
and  half  tones. 
The  latest  mode  of  working  is  now  to  give  a  good  expos- 
ure for  detail,  and  in  developing  get  out  all  you  can  ;  but 
do  not  over  expose  or  develop,  so  as  to  have  a  flat  or  fogged 


PROCESSES  OF  MR.  T.  C.  ROCHE. 


543 


negative.  For  general  work  a  well-lighted  picture  will  not 
require,  if  your  chemicals  are  in  good  working  condition,  any 
redeveloping  or  intensify-  ^.  lg 

ing,  by  using  Anthony7 s  new 
negative  collodion.  Some  of 
the  best  landscape  photog- 
raphers have  been  for  some- 
time developing  inthe  field, 
and  fixing  at  home  in  the 
evening  or  next  morning. 
The  mode  is  as  follows : 
After  developing  the  plate, 
wash  off  with  water,  or  put  the  negative  in  a  dish  with  good 
water,  enough  to  rock  the  plate  in.  When  all  the  greasy 
lines  disappear,  flow  over  the  plate  a  solution  of  glycerine  : 

Glycerine,  1  ounce. 

Water,  3  ounces. 

Alcohol,  •  1  ounce. 

Then  put  the  plate  in  the  Fig' 
negative  box,  and  keep  on 
taking  negatives.  When 
you  get  home  (those 
plates  with  glycerine  on 
will  keep  a  week  or  more) 
wash  off  the  glycerine,  - 
fix  the  negative  in  weak 
cyanide,  wash  well,  and 
force  up,  if  required,  with 
any  of  the  well-known 
methods.  I  prefer,  after 
fixing,  to  flow  over  the  plate  an  acid  solution  of 

Acetic  acid,  No.  8,  4  ounce. 

Water,  .  .      .4  ounces. 

I  then  drain  and  flow  a  solution  of  pyrogaltic  acid,  No.  1, 
mixed  with  a  few  drops  of  acid  silver,  as  per  formula  No.  2. 

'  No.  1. 

Pyrogallic  acid,       ........  60  grains. 

Water,   20  ounces. 

Citric  acid,   20  grains. 

No.  2. 

Silver,   20  " 

Citric  acid,   20  " 

Water,   1  ounce. 


544 


PROCESSES  OP  MB.  T.  C.  ROCHE. 


This  will  bring  the  negative  up  to  a  good  printing  color,  and 
will  not  change.    Dry  and  varnish. 

Keep  your  shield  and  box  free  from  dust  in  working,  and 
take  an  interest  in  your  apparatus. 

Cameras  and  Lenses  for  Field  Work. 

Fis» 18-  One  R  success  view  cam- 


era, with  double  swing  back 
and  folding  bed,  for  eight  by 
ten  plate;  one  Dallmeyer  wide 
angle  rectilinear  ;  one  Dall- 
meyer rapid  rectilinear. 

By  taking  off  the  front 
combination  from  either  you 
lengthen  the  focus,  and  can 
get  a  larger  view. 

For  Stereoscopic  Work. 

One  eight  by  five  Z  success 
camera  box,  one  pair  Dall- 
meyer wide  angle  rectilinear, 
two  and  a  half  inch  focus,  one 
pair  Dallmeyer  rapid  rectilin- 


ear, and  one  pair  Dallmeyer  four  and  a  half  quick-acting 
stereoscopic  landscape  lenses. 


Fig.  19. 


CHAPTEE  LXV. 


DEFECTS  AND  BEMEDIES. 


1.  Fogging. 

Fogging  arises  from  various  causes,  which  generally  are 
easily  detected.  A  fog  which  is  uniform  over  the  plate,  and 
can  be  readily  rubbed  off  with  the  finger,  is  caused  by  the 
condition  of  the  chemicals.  The  fog  caused  by  improper 
action  of  light  on  the  plate  de- 
velopes  in  the  film,  and  not  on  Flg'  20* 

the  surface.  This  rule  will 
generally  indicate  to  the  oper- 
ator in  what  direction  to  look 
for  the  cause.  The  intrusion 
of  light  may  be  through  small 
holes  in  the  wood  work  of  the 
box,  or  in  the  bellows,  or  the 
cut  off  in  the  plate  shield  may 
not  operate,  or  the  shield  may 
not  fit  closely  in  its  place  in 
the  box. 

If  the  chemicals  are  at  fault, 
the  causes  are  found  in  either 
the  bath  or  the  collodion  or  the 
developer.  A  very  light  col- 
ored collodion  will  sometimes 
be  the  cause — the  remedy  is 
the  addition  of  a  little  tincture 
of  iodine.  If,  while  using  a 
ripe  collodion  of  a  deep  straw 
color,  fog  should  occur,  the 
fault  is  probably  in  the  bath 
— a  drop  of  nitric  acid  to  each 
twenty  ounces  of  the  bath  will 
be  sufficient  in  case  the  bath  has  been  neutral.  If  this  does 
not  remedy  the  fog,  the  cause  may  be  organic  matter  in  the 
bath.  The  remedy  for  this  is  to  neutralize  the  bath  with 
bi-carbonate  of  soda  and  allow  to  stand  in  the  sunlight  until 


546 


DEFECTS  AND  REMEDIES. 


all  precipitation  ceases 
and  the  bath  has  become 
clear.  Then  filter  and  try 
a  negative.  A  little  ni- 
tric acid  may  be  needed. 

Unclean  glass  is  fre- 
quently a  cause  of  fog  : 
this  can  readily  be  de- 
tected by  its  appearance, 
as  it  is  always  found  be- 
tween the  collodion  and 
glass. 

Hard  rubber  baths 
sometimes  contaminate  a 
silver  solution.  Before 
being  used  they  should 
be  cleansed  by  using  a 
strong  alkaline  wash,  and 
while  being  used  the  sil- 
ver solution  should  never 
be  left  in,  but  should  be 
poured  out  and  the  bath 
washed  as  soon  as  the 
day's  work  is  done. 

Lime  water,  rain  water 
collected  from  the  roofs 
of  houses,  and  water  containing  alkaline  salts,  if  used  in  the 
develop,  may  cause  fog. 

The  vapor  of  ammonia,  or  the  presence  of  sulphuretted  hy- 
drogen,  will  cause  an  undue  deposit 
of  silver  on  the  plate. 

Fogging  is  sometimes  caused  by 
removing  the  glass  from  a  cool 
place  and  taking  it  into  a  warm, 
damp  room — a  coat  of  moisture  is 
thus  produced  upon  the  plate  which 
is  sure  to  cause  fogging. 

The  vapor  of  turpentine  destroys 
the  sensitiveness  of  iodide  of  silver. 

If  the  temperature  of  the  bath 
and  developer  are  too  high,  fogging 
ensues.  If  the  temperature  be  too 
low,  the  chemicals  do  not  combine 
properly  ;  consequently,  in  very  hot 
weather  or  very  cold,  means  should 


DEFECTS  AND  REMEDIES. 


547 


be-  used  to  regulate  the  Fis-  23« 

temperature  of  the  bath 
and  developer.  The  tem- 
perature should  range 
from  fifty-five  to  seventy 
degrees  Fahrenheit. 

A  slight  fog  may  fre- 
quently be  removed  by 
pouring  upon  the  devel- 
oped plate,  after  it  has 
been  fixed  and  well 
washed,  a  solution  of  io- 
dine and  iodide  of  potas- 
sium in  water.  This  pro- 
duces a  very  thin  coating 
of  iodide  of  silver,  which 
can  be  removed  by  im- 
mersing again  in  the  fix- 
ing bath .  Collodion  tran- 
sparencies that  may  have 
been  over-developed  can 
be  rendered  clear  by  this 
means. 

A  change  of  tempera- 
ture may  cause  a  film  of 
moisture  on  the  lens — this 
would  necessarily  pro- 
duce fog  on  the  plate. 

A  great  excess  of  diffused  light  in  the  skylight  room  is  a 
frequent  cause  of  veiling 'of  the  plate.  To  prevent  this,  a 
black  hood  of  some  kind  should  surround  the  lens,  extending 
some  distance  in  front  of  it,  to  cut  off  side  light. 


2.  Thinness  of  the  Film. 

The  collodion  may  not 
have  sufficient  soluble  cot- 
ton, or  may  be  under-io- 
dized. 

An  old  collodion  may 
make  a  very  thin  coating 
upon  the  plate. 


Fig.  24. 


25 


DEFECTS  AND  REMEDIES. 


3.  Irregularity  of  the  Film. 

Crapy  Lines. — S  o  m  e- 
times  caused  by  too  much 
water  in  the  collodion.  If 
the  operator  makes  his 
own  collodion,  he  should 
be  careful  to  use  a  dry 
bottle,  or  in  case  the  bot- 
tle is  freshly  washed,  it 
should  be  well  rinsed  with 
alcohol . 

Sometimes  caused  by 
neglect  to  change  the  po- 
sition of  the  plate  while 
the  collodion  is  draining 

Ridges. — Collodion  too 
thick.  A  large  excess  of 
alcohol.    Gummy  cotton. 

Mottling  arises  from 
the  undue  thickness  of  col- 
lodion, caused  by  the  evap- 
oration of  the  solvents. 

4.  Defects  in  the  Image. 

Too  much   Contrast  is 
caused  generally  by  un- 
der exposure.     Too  little 
bromide  in  the  collodion, 
or  too  much.    Acid,  old 
collodion.    Too  little  cotton  in  the 
collodion.     Old,  disordered  nitrate 
bath.    Cotton  working  too  intense. 

Too  little  Contrast. — Over-expos- 
ure. A  collodion  not  sufficiently 
acid. 

As  a  general  rule,  very  strong 
negatives  must  be  printed  on  paper 
floated  on  a  weak  nitrate  bath,  and 
printed  in  the  sun.  A  weak  nega- 
tive should  be  printed  on  paper 
floated  on  a  strong  nitrate  bath,  and 
be  printed  in  the  shade. 


DEFECTS  AND  BEMEDIES. 


549 


Half  Tone, — Strong  contrasts  in  portraiture  are  not  as 
popular  as  they  once  were.  To  secure  half  tone  give  plenty 
of  exposure,  and  use  a  rather  weak  developer.    After  the 

Pig.  27. 


4f 


details  are  brought  out,  finish  with  a  strong  developer,  in 
order  to  give  strength  to  the  lights.    Delicacy  of  modelling 
can  also  be  aided  by  allowing  the  developer  to  remain  on 
~   0Q  the  plate  with-  „.  „ 

Flg>28-        , out  moving.  p*-29- 

Flowing  the  de-  ^^^^ 
veloper  back-  ^  f 
ward   and  for-  (T*^^ 
ward  on  the 
*^s*     plate  tends  to 
harshness  of  im- 
age. 

5.  Blurring  is 
generally 
c  a  u  s  ed  by  a 
strong  light  and 
dark  shadow 
side  by  side.  The 
light  may  be  re- 
flected from  the 
back  of  the 
glass,  and  thus 
cause  an  im- 
proper effect  in 
the  film.  This 
effect  is  very  perceptible  in  taking 
interiors,  where  the  light  from  the 
windows  is  received  directly  upon  the  plate.  It  also  oc- 
curs in  taking  landscapes  where  dark  objects  are  projected 
against  a  strongly  lit  sky.  This  trouble  occurs  more  in  dry 
plates  than  in  wet.    To  prevent  it  in  dry  plates,  coat  the 


550 


DEFECTS  AND  REMEDIES. 


Fig.  31. 


back  of  the  negative  before  exposure  with  a  surface  that 
will  absorb  the  light  that  passes  through  the  film,  and  in  wet 
plates  press  a  piece  of  wet,  dark-red  blotting  paper  against 
the  back  of  the  negative. 

6.  Stains  of  Irregular  Development. — Caused  either  by  the 
developer  not  being  flowed  evenly  upon  the  plate,  or  by  excess 
of  ether  and  alcohol 
in  the  bath.  If  the. 
latter  be  the  case, 
add  some  alcohol  to 
the  developer.  Asa 
general  rule,  it  is  bet- 
ter to  avoid  the  use 
of  alcohol  in  the  de- 
veloper, as  it  has 
been  found  to  have  a 
tendency  to  cause  a 
crystallization  in  the 
film,  and  thus  pro- 
duce pin  holes  in 
washing. 

Thin,  weak  Nega- 
tives quite  frequent- 
ly are  obtained  in 
taking  a  view  from 
an  elevation  in  warm 
weather.  This  arises 
from  the  refraction 

of  the  rays  of  light  passing  through  strata 
of  air  of  different  densities.    There  is  no 
remedy  for  this  trouble  except  to  take  the 
view  on  a  cloudy  day. 


Splitting  and  Slipping 
Fig.  32 


decomposed  collodion. 


of  the  Film.— 1.  Collodion  not  suffi- 
ciently set  before 
immersion  in  the 
bath.  2.  Damp 
glass.  3.  Too 
much  iodizing  in 
the  co  llodion. 
4.  Too  contract- 
ile cotton. 

Splitting  in 
Washing. — B  a  d 
cotton  and  old 


DEFECTS  AND  BEMEDIES. 


551 


Splitting  in  Drying. —  Fig«  33» 

Whatever  may  be  the 
cause  of  this  trouble,  it 
may  be  remedied  by  flow- 
ing the  plate,  after  being 
washed,  with  a  weak  so- 
lution of  gum  Arabic,  say 
twenty  grains  to  the 
ounce  of  water. 

Slipping  of  the  Film. — 
Immersing  too  soon  in  the 
bath.  A  very  acid  silver 
bath.  An  acid  surface  of 
the  glass.  A  solution  of 
albumen  will  prevent  the 
above  irregularities. 

7.  Want  of  Sharpness. 

Taking  it  for  granted 
that  the  operator  is  supplied  with  a  good  lens,  care  must  be 
taken  to  keep  the  position  of  the  glass  in  the  shield  identical 
with  that  of  the  ground  _.    _ . 

glass,  otherwise  the  pic- 
ture will  lack  sharpness. 
In  case  the  lenses  have 
been  taken  out  and 
cleaned,  they  must  be 
put  together  again  in 
their  proper  position. 
The  arrangement  of  the 
different  parts  of  an  ob- 
jective can  be  seen  by 
referring  to  page  561.  In 
taking  views,  shaking 
of  the  box  will  cause 
lack  of  sharpness.  As 
the  moving  of  the  box 
is  likely  to  be  caused 
solely  by  a  strong  wind, 
operators  should  be 
careful  to  have  a  very 
stiff  tripod  for  this  pur- 
pose. 


552 


DEFECTS  AND  BEMEDIES. 


8.  Streaks 


Fig.  35. 


Arise  from  a  variety  of  causes.     1.  If  the  plate  be  im- 
mersed before  the  collodion  is  sufficiently  set,  streaks,  com- 
mencing at  the  bottom  of 
the  plate  and  extending  up- 
ward, sometimes  occur.  2. 
Not  moving  the  plate  after 
immersion  in  the  bath.  In 
all  cases,  immediately  after 
placing  the  plate  in  the 
bath,  it  should  be  moved 
both  vertically  and  horizon- 
tally for  a  short  time,  other- 
wise streaks  in  the  direc- 
tion of  the  dip  are  likely  to 
occur.     3.  Streaks  across 
the  plate  at  right  angles  to 
the  line  of  dip  are  caused 
by  irregularity  of  motion 
in  dipping  the  plate.    It  is 
very  important  to  acquire 
a  uniform,  steady  movement  of  the  hand  in  dipping  the  plate, 
and  care  should  be  taken  not  to  lift  the  upper  portion  of  the 

plate  out  of  the  solution 
*  until  it  has  been  some- 
time immersed,  as  by  so 
doing  marbled  stains  and 
rings  are  apt  to  be  formed 
on  the  exposed  part.  4. 
In  case  any  foreign  solu- 
tion should  become  mixed 
with  the  developer  at  the 
time  of  pouring  upon  the 
plate,  such  as  the  drip- 
pings of  former  develop- 
ments running  off  the  bot- 
tom of  the  developing 
glass,  unpleasant  stains 
will  occur.  To  avoid  this, 
keep  a  rag  or  piece  of 
blotting  paper  ready  to 
absorb  any  fluid  that  may 
be  found  on  the  bottom  of 
the  glass.    5.  Streaks  of 


DEFECTS  AND  REMEDIES. 


553 


Fig.  37. 


a  zigzag  shape  sometimes  will  be  found  proceeding  from  the 
point  where  the  dipper  touched  the  plate.  This  is  more  likely 
to  occur  with  hard  rubber  dippers  than  glass  or  porcelain. 
To  avoid  this  trouble,  dip  the  plate  slowly.  6.  Keversing 
the  position  of  the  plate  after  taking  it  out  of  the  bath  is 
likely  to  cause  streaks.  As  a  general  rule,  the  direction  of 
the  drainage  of  a  plate  should 
not  be  changed  from  the  time 
of  removal  from  the  bath  until 
the  application  of  the  devel- 
oper. 7.  Using  the  dusting 
brush,  care  must  be  taken  to 
have  the  broad  brush  used  to 
clean  dust  from  the  surface  of 
the  plate  perfectly  dry.  8. 
Streaks  in  the  direction  of  the 
dip  are  caused  by  lack  of  acid 
in  the  bath.  The  obvious  rem- 
edy is  to  add  carefully  a  little 
nitric  acid. 

9.  Spots  and  Pin  Holes. 

Occur  from  two  or  more 
causes — dust  and  crystals  of 
iodo-nitrate  of  silver.  These, 
occurring  upon  the  face  of  the  negative,  prevent  the  action 
of  the  light  upon  the  film  beneath  them,  and  when  the  nega- 
tive is  fixed  and  washed,  Fi  3g 
transparent  spots  are 
found  where  they  were 
located. 

If  the  dust  come  from 
the  bath,  it  can  be  fil- 
tered out.  If  it  come 
from  an  unclean  apart- 
ment, sprinkle  the  floor 
thoroughly  with  water. 

To  remedy  the  forma- 
tion of  the  iodo-nitrate 
of  silver,  all  that  is  nec- 
essary is  to  precipitate 
from  the  solution  the  excess  of  iodide  of  silver,  which  facili- 
tates their  formation.  The  usual  and  best  mode  of  doing 
this  is  to  take  one-fourth  the  quantity  of  your  bath  of  water 


554 


DEFECTS  AND  BEMEDIES. 


Fig.  39. 


and  pour  the  bath  into  it.  This  will  precipitate  considerable 
iodide  of  silver,  which  must  be  filtered  out.    Then  boil  the 

bath  down  to  the  original 
amount,  having  first  neu- 
tralized it  with  a  little  am- 
monia or  bi-carbonate  of 
soda  ;  stand  it  in  the  sun 
for  a  few  days.  Subse- 
quently, if  necessary,  add 
a  very  small  quantity  of 
nitric  acid. 

Large,  semi-transpar- 
ent places  occur  some- 
times when  the  developer 
is  poured  on.    This  is  oc- 
casioned by  a  lack  of 
acetic  acid  in  the  devel- 
oper.   If  the  bath  should 
not  be  sufficiently  iodized, 
the  iodide  of  silver  formed 
in  the  film  is  dissolved 
out,  commencing  at  the  edges  of  the  plate.    Plates  that  are 
kept  too  long  before  development  sometimes  become  injured 
by  the  increased  strength  of  the  silver  solution,  caused  by 

the  evaporation   of  the 
Fig.  40.  water,  and  the  iodide  of 

silver  as  in  the  former 
case  being  partially  dis- 
solved, and  the  coating 
thus  rendered  thinner. 

10.  Comets,  etc., 

Are  intense  opaque  spots, 
which  are  not  observed 
generally  before  develop- 
ment. Their  general  ap- 
pearance, as  the  name  in- 
dicates, is  that  of  a  nu- 
cleus and  a  tail  attached. 
The  causes  of  these  are 
various  ;  but  the  princi- 
pal one  is  the  pressure  of 
some  substance  tending 
to  a  strong  reduction  of 


DEFECTS  AND  KEMEDIES. 


555 


Fig.  41. 


the  nitrate  of  silver,  particles  of  protosulphate  of  iron,  of 
hyposulphite  of  soda,  that  may  exist  as  dust  in  the  dark 
room,  unfiltered  collodion  or  pieces  of  dry  collodion  from  the 
lip  of  the  collodion  vial,  and  metallic  particles  coming  from  the 
hinges  of  the  door  of  the 
shield.  Where  the  comets 
occur  from  the  condition  of 
the  collodion,  which  is  fre- 
quently the  case,  the  addi- 
tion of  tincture  of  iodine  to 
it  will  entirely  remedy  the 
evil.  Tincture  of  iodine 
should  never  be  added  in  ■ 
such  quantity  as  to  produce  | 
a  deeper  tint  than  a  lemon 
color. 

11.  Stains  and  Surface 
Markings. 

Oyster  shell  markings,  also  called  "  matt  silver/'  consist 
of  metallic  silver  reduced  locally  by  the  action  of  the  devel- 
oper. They  generally  42 
occur  when  the  plate  has 
been  kept  a  long  while 
before  development,  and 
in  contact  with  a  surface 
from  which  the  silver  so- 
lution upon  the  surface 
may  become  contamina- 
ted with  organic  matter 
or  a  solution  of  some  me- 
tallic salt.  The  forma- 
tion of  these  spots  is  very 
capricious,  and  they  fre- 
quently occur  on  parts  of 
the  plate  the  least  sus- 
pected. In  the  early 
days  of  photography,  a 
collodion  made  with  the 
iodide  of  ammonium  then 
manufactured  was  especially  subject  to  these  and  other  sur- 
face markings.  The  explanation  seems  to  be,  that  in  the 
decomposition  of  the  iodide  of  ammonium  and  the  formation 
of  iodide  of  silver,  an  excess  of  ammonia  may  be  eliminated, 


556 


DEFECTS  AND  KEMEDIES. 


which  reduces  a  little  of  the  nitrate  of  silver  to  the  state  of 
oxide  of  silver.  This  attaches  itself  to  the  film  and  produces 
sometimes  one  kind  of  marking  and  sometimes  another.  The 
remedy  in  this  case  would  seem  to  be  to  increase  the  acidity 
of  the  bath.  As  the  larger  and  heavier  of  these  stains  ap- 
pear to  proceed  from  the  re- 
action of  the  drained  silver 
solution  upon  the  film,  the 
best  way  to  prevent  the 
trouble  is  to  absorb  the 
drained  solution  by  means 
of  a  piece  of  blotting  paper 
placed  under  the  plate,  ex- 
tending from  one  corner  to 
the  other. 

Brown  Stains. — In  case  it 
is  found  necessary  to  rede- 
velop with  pyrogallic  acid 
after  fixing,  care  must  be 
taken  to  remove  all  the  hy- 
posulphite, otherwise  the 
plate  will  be  stained  a 
transparent  brown  in  the 
.  shadows. 


Defects  in  Paper  Prints. 


Fipr.  44. 


1.  Weak  Prints. — Nega- 
tive too  thin — remedy, 
make  silver  bath  strong 
and  print  in  the  shade. 
The  use  of  nitrate  of  mag- 
nesia or  nitrate  of  alumi- 
na in  connection  with  ni- 
trate of  silver  facilitates 
the  printing  of  weak  neg- 
atives. 

2.  Harsh  Black  and 
White  Prints. — Negative 
too  intense — remedy,  re- 
d  u  c  e  materially  the 
strength  of  the  silver  bath 

and  print  in  the  sunshine. 

3.  Yellow  Whites.— A  strongly  acid  silver  bath  ;  allowing 


DEFECTS  AND  KEMEDIES. 


557 


the  prints  to  remain  without  constant  motion  in  the  fixing 
bath  ;  allowing  them  to  remain  an  unnecessary  long  time  in 
the  fixing  bath ;  the  presence  of  acid  gold  upon  the  paper 
when  placed  in  the  fixing  bath.  A  method  of  obviating  some 
of  the  above  troubles  is  to  immerse  the  toned  prints  first  in 
a  weak  solution  of  nitrate  of  silver — this  will  reduce  the 
chloride  of  gold  and  strengthen  the  tone  ;  subsequently,  put 
in  a  moderately  strong  solution  of  salt  and  carbonate  of  soda 
— this  will  convert  the  silver  into  chloride  of  silver,  and  neu- 
tralize the  print  at  the  same  time.  Now,  when  the  print 
goes  into  the  fixing  bath,  there  will  be  nothing  present  to 
cause  the  yellow  color  of  the  whites.  Sometimes,  where  the 
washing,  toning,  and  fixing  are  done  in  the  same  apartment, 
hyposulphite  is  spilled  upon  the  floor,  dries,  is  ground  to  dust 
by  the  feet,  pervades  the 
air  of  the  room,  gets  into 
the  water  of  the  washing 
tank,  and  turns  the  whites 
yellow  before  the  prints 
#0  into  the  toning  bath. 
No  well  arranged  gallery 
should  have  the  washing 
and  fixing  vessels  in  the 
same  apartment.  They 
should  be  separated  as  far 
as  possible. 

4.  Prints  do  not  Tone 
Readily. — This  generally 
arises  from  the  presence 
of  a  mineral  acid  in  the 
print  or  in  the  gold  bath 
in  combination  with  the 
gold.  To  remedy  the 
trouble  in  the  print,  al- 
ways neutralize  the  silver 
solution  with  ammonia  before  using,  and  subject  the  paper 
before  printing  to  the  vapor  of  ammonia  from  ten  to  fifteen 
minutes.  If  a  blue  scum  appear  upon  the  surface  of  the 
paper  after  fuming  witn  ammonia,  it  is  proof  that  the  silver 
bath  is  acid  with  nitric  acid,  the  blue  scum  being  nitrate  of 
ammonia.  This  can  be  removed  by  breathing  upon  the  sur- 
face of  the  paper.  To  prevent  the  presence  of  free  acid  with 
the  gold  in  the  toning  bath,  the  chloride  of  gold  should  al- 
ways be  kept  dissolved  in  a  stock  bottle.  Before  being  used, 
all  the  acidity  should  be  removed  by  adding  chalk  and  heat- 


558 


DEFECTS  AND  KEMEDIES. 


Fig.  46. 


Fig.  47. 


ing  for  some  time  to  about  one  hundred  and  thirty  degrees 
Fahrenheit,  or  by  adding  salt  and  carbonate  of  baryta.  In 
the  latter  case  no  heat  should  be  used,  and  the  mixture  should 
be  shaken  occasionally  for  two  or  three  days.  In  either  case 
the  solution  is  always  ready  to  add  to 
the  toning  bath,  which  need  not  be 
changed,  but  can  be  kept  for  months, 
thus  greatly  economizing  the  expense 
of  gold.  Paper  kept  too  long  after 
printing  is  frequently  very  difficult  to 
tone.  In  fuming  the  paper  with  ammo- 
nia, care  should  be  taken  to  have  the 
whole  surface  equally  acted  upon,  other- 
wise lines  and  streaks  will  occur,  owing 
to  the  unequal  action  of  the  ammonia. 

5.  The  Silver  Bath  becomes  Discolored. — The  solution  is 
either  acid  or  not  sufficiently  strong. 

6.  Tears  of  Solution  remain  on  the  Paper,  and  Causing  Brown 
Spots. — This  most  frequently  occurs  on  high  gloss  papers. 
The  remedy  is  to  wipe  the  surface  of  each  sheet  well  with  a 

clean  piece  of  cotton  flannel.  Some 
persons  recommend  a  little  glycerine 
in  the  silver  solution,  and  others, 
placing  the  paper  in  a  damp  cellar 
for  two  or  three  days  before  using. 

7.  Stains  occur  from  various 
causes.  A  brown  stain  may  occur 
from  a  trace  of  hyposulphite  on  the 
hands.  Brown  stains  with  blue  me- 
tallic surface  comes  from  solutions 
of  hyposulphite  coming  in  contact 
with  the  print  before  toning.  Yellow  stains  on  the  surface, 
varying  in  size,  come  from  acid  bubbles  beneath  the  print  in 
the  fixing  bath.  To  avoid  this,  fix  prints  face  upward.  The 
handling  or  touching  the  surface  of  the  paper 
with  sweaty  or  wet  fingers  will  cause  stains. 
Black  spots  in  the  paper  after  silvering  arise 
from  different  causes.  1.  Metallic  particles 
in  the  paper.  2.  Dust  of  sulphate  of  iron  or 
particles  of  hyposulphite  of  soda  becoming 
attached  to  it  through  carelessness.  3,  By 
using  hard  rubber  dishes  for  the  silver  solu- 
tion. These  become  gradually  acted  upon 
by  the  silver,  and  small  particles  float  upon  the  surface  and 
attach  themselves  to  the  paper.  Never  use  hard  rubber  for 
floating  bath. 


Fig.  48. 


DEFECTS  AND  EEMEDIES. 


559 


Fig.  49. 


8.  Mottling ,  or  Irregular  Action  of  the  Silver,  can  arise  from 
too  short  floating,  too  weak  silver,  silver  solution  being  too 
cold,  a  large  quantity  of  alcohol  in  the  silver  solution.  The 
remedy  in  either  case  is  obvious. 

9.  Scum  on  the  Silver  Solution. — In  all  cases  where  the  sil- 
ver solution  has  been  used  for  sensitizing  paper,  and  is  al- 
lowed to  stand  some  time  without  being  used,  a  scum  of 
reduced  silver  and  organic  matter  collects  on  the  surface. 
This  must  be  removed  by  drawing  the  edge  of  a  piece  of  stiff 
paper  over  the  surface. 

10.  Blurring. — Want  of  contact  between  the  surface  of  the 
paper  and  the  negative.  This  is  fre- 
quently caused  by  dampness  of  the 
padding  used  for  pressing  the  paper 
against  the  negative.  Always  thor- 
oughly dry  the  pads  before  using,  and 
take  the  precaution  to  thoroughly  di- 
vest them  of  dust. 

11.  Blistering  generally  occurs  on 
highly  albumenized  papers.  Whatever 
the  cause,  it  may  be  obviated  by  soak- 
ing the  prints  after  removal  from  the 
fixing  bath  in  a  solution  of  salt,  say  twenty  to  thirty  grains 
to  the  ounce  of  water,  for  a  quarter  of  an  hour.  Then  wash 
them. 

12.  Fading  of  Prints  generally  occurs  from  the  presence 
of  hyposulphite  of  silver  in  the  paper.  Damp- 
ness will  cause  fading  ;  consequently  all 
prints,  in  being  put  up,  should  be  protected 
as  much  as  possible  from  the  action  of  moist- 
ure in  the  air.  The  best  way  now  known 
to  eliminate  hyposulphite  of  silver  is  to  soak 
the  prints,  after  they  have  been  rapidly 
washed  in  four  or  five  changes  of  water,  in 
a  solution  of  acetate  or  nitrate  of  lead.  The 
strength  of  this  solution  may  depend  upon 
the  number  of  prints  to  be  treated,  and  may 
vary  from  half  a  grain  to  two  grains  to  the 
ounce  of  water.  The  action  is  very  rapid, 
and  the  time  of  washing  and  the  quantity 
of  water  for  washing  very  much  reduced.  ^ 

13.  Cracking  of  the  Albumen  Coating  arises  from  excessive 
thickness.  In  case  it  is  observed,  be  careful  not  to  dry  the 
prints  before  they  are  mounted,  and  dampen  the  mounting 
card  in  order  that  it  may  shrink  conformably  with  the  print. 


Fig.  50. 


560 


COLLODIO-CHLORIDE. 


Collodio-Chloride. 

Fading,  as  in  paper  prints,  is  due  to  the  presence  of  the 
hyposulphite  of  silver.    Remedy,  soaking  in  the  lead  solution 

just  described. 

Unsatisfactory  Toning. — 
The  presence  of  free  nitrate 
of  silver  in  the  film.  Remove 
this  by  soaking  for  some  time 
in  a  weak  solution  of  a  veg- 
etable acid,  and  tone  in  a  bath 
made  with  carbonate  of  mag- 
nesia and  some  neutralized 
gold. 

Flat  Blue  Prints. — Pres- 
ence of  moisture  in  the  film. 
The  collodio-chloride  plate 
and  the  negative  should  both 
be  perfectly  dry  and  warm 
before  being  put  out  to  print. 

In  all  photographic  operations  the  greatest  care  should  be 
taken  to  systematically  avoid  the  mixing  or  mingling  in  any 
way  of  vessels  or  chemicals  used  for  different  purposes.  Es- 


Fig.  52. 


pecially  should  great  care  be  taken  to  prevent  the  contact 
of  the  hyposulphite  of  soda  with  the  vessels  or  materials,  ex- 
cept in  its  proper  place,  of  a  fixing  bath. 


MISPLACEMENT  OF  LENSES. 


561 


Misplacement  of  Lenses. 


It  frequently  occurs  that  photographers,  after  separating 
the  combinations  of  lenses  for  cleansing  and  other  purposes, 


meniscus,  and  C  the  crown  lens  of  the  back  combination,  in 
their  proper  positions. 

This  will  enable  those  who  are  in  trouble  to  determine  for 
themselves  if  their  lenses  are  in  proper  position  or  not,  and 
in  many  cases  it  will  save  them  express  charges. 

The  foregoing  rule  does  not  apply  to  the  Dallmeyer  lenses, 
in  which  the  curves  and  positions  of  the  various  lenses  are 
entirely  different,  and  each  lens  so  fastened  in  its  cell  that 
it  is  impossible  to  misplace  either  of  them. 


misplace  them. 


The  cut  is  given  to  show 
the  correct  position  of  each. 
A  is  the  front  combination, 
the  lenses  of  which,  being 
hermetically  sealed,  are  sel- 
dom misplaced.  In  fact,  we 
have  noticed  that  some  man- 
ufacturers fasten  the  front 
combination  in  its  cell. 


F   represents    the  flint 


CHAPTEE  LXVI. 


f 


PRINTING  ON  ALBUMENIZED  PAPER. 


Fig.  53. 


The  improved  methods  of  working  albumenized  paper  have 
made  the  results  more  certain,  while  the  care  is  very  mate- 
rially lessened.  The  formula  most  generally  used  at  present 
is  as  follows  :  Make  a  solution  of  nitrate  of  silver  from  thirty 
to  forty -five  grains  to  the  ounce  of  water.  Add  a  few  drops 
of  ammonia,  shake  thoroughly,  and  then  allow  the  precipitate 
to  settle  ;  decant  and  add  two  grains  of  ammonia-alum  to 
each  ounce  of  the  solution.  Float  the  paper  one  minute  and 
expose  to  the  vapor  of  ammonia  as  long  as  may  be  found 
necessary.  In  cold  weather  the  solution  should  be  kept  at  a 
moderate  temperature,  and  the  ammonia  box  should,  if  nec- 
essary, be  slightly  warmed  by  placing  a  hot 
brick  in  it.  In  very  cold  weather,  priuting  in 
the  open  air  is  liable  to  be  unsatisfactory,  and 
many  persons,  who  are  not  aware  of  the  cause 
of  imperfect  prints  produced  under  such  circum- 
stances, improperly  condemn  the  materials. 

Before  toning,  the  prints  should  be  soaked 
for  fifteen  minutes  in  a  weak  solution  of  some 
vegetable  acid.  If  glacial  acetic  acid  be  used, 
ten  drops  to  the  quart  is  sufficient ;  if  good 
acetic  acid,  No.  8,  be  used,  a  dram  to  the  quart 
is  sufficient.  A  similarly  weak  solution  of 
either  citric  or  oxalic  acid  can  also  be  employed. 
Subsequently,  rinse  the  prints  in  two  changes 
of  water,  and  they  are  ready  to  be  toned. 


Toning  Bath. 


The  principal  point  to  be  attained  in  prepar- 
ing a  toning  bath  is  to  get  a  stock  of  neutral  gold  solution. 
This  can  be  done  in  two  ways.  Dissolve  the  ordinary  chloride 
of  gold  in  water  in  the  proportion  of  fifteen  grains  to  the 
ounce,  and  neutralize  the  solution,  adding  either  a  little  carbon- 
ate of  baryta  or  prepared  chalk.  If  the  first,  do  not  warm  the 
solution,  but  shake  it  well  occasionally  for  two  or  three  days  ; 


PRINTING  ON  ALBUMENIZED  PAPER.  563 


if  the  second,  a  little  heat  should  be  used.  The  solution  is 
now  ready  for  use  in  toning.  All  that  is  necessary  is  to  put 
as  much  of  the  gold  solution  as  may  be  desired  in  the  water, 
add  about  thirty  grains  of  salt  to  the  pint,  and  a  very  small 
quantity  of  any  of  the  alkaline  salts  ordinarily  used  for  that 
purpose.  By  proceeding  thus,  a  permanent  toning  bath  is 
made,  which  can  be  used  day  after  day  by  merely  adding 
gold  when  required,  and  a  little  salt  and  alkali  when  nec-  t 
essary.  This  operation  is  so  simple,  that  it  is  not  considered 
necessary  to  give  any  set  formula  for  making  a  toning  bath. 
We  desire  to  call  particular  attention  to  washing  in  weak 
acid  solution  spoken 
of  above,  as  it  saves 
time,  water,  gold, 
and  insures  ease  of 
toning. 

After  toning,  the 
prints  should  be 
well  washed  and 
placed  in  the  fixing 
bath,  one  by  one, 
face  up.  The  top 
1  ayer  should  be 
placed  face  down. 
The  object  of  plac- 
ing them  face  up  is 
to  avoid  the  spots 
which  occur  when  a 
bubble  of  air  gets 
under  the  prints. 
They  should  be  fre- 
quently moved 
while  in  the  bath  to 
insure  uniformity  of 
action.  To  avoid  the  risk  of  blisters,  which  frequently  occur 
on  highly  albumenized  paper,  the  prints  should  be  transferred 
after  they  are  fixed  to  a  solution  of  common  salt,  of  the 
strength  of  fifteen  grains  to  the  ounce  ;  in  about  a  quarter 
of  an  hour  they  should  be  placed  in  the  washing  tank. 

As  it  is  important  to  know  when  all  the  hyposulphite  of 
soda  has  been  removed,  the  water  should  be  tested.  The 
test  ordinarily  used  is  very  simple  and  thorough.  Make  a 
thin  fluid  solution  of  starch,  put  a  little  of  this  in  a  large 
mouthed  vial,  and  add  to  it  a  drop  of  aqueous  solution  of 
iodine  :  blue  iodide  of  starch  is  instantly  formed.    Now  add 


Fig.  54. 


564 


PRINTING  ON  ALB UMENIZED  PAPER. 


a  little  of  the  water  in  which  the  prints  are  washing.  If 
there  be  any  hyposulphite  in  the  water,  the  blue  color  will 
be  immediately  discharged.  If  the  mixture  in  the  vial  re- 
main blue,  it  is  evident 
there  is  no  hyposulphite 
in  the  water.  It  is  impos- 
sible to  give  rules  for  the 
time  of  washing  ;  but 
where  large  quantities  of 
prints  are  washed  togeth- 
er in  running  water, 
which  comes  in  at  the 
bottom  and  flows  away  at 
the  top  of  the  tank,  about 
three  hours  are  necessary. 
During  the  progress  of 
the  washing,  the  water 
should  be  entirely  drawn 
off  two  or  three  times. 

A  method,  shortening 
the  time  and  trouble  of 
washing,  and  at  the  same  time  insuring  the  absence  of  hypo- 
sulphite of  soda,  has  been  proposed  and  is  practiced  by  Mr. 
H.  J.  Newton,  of  New  York.  After  entirely  changing  the 
water  a  number  of  times,  he  soaks  the  prints  for  a  short  time 
in  a  very  weak  solution  (a  half  grain  to  an  ounce  of  water) 
of  acetate  or  nitrate  of  lead.    The  affinity  of  sulphur  for  lead 

forms  sulphite  of 
lead,  which  is  insolu- 
ble, and  the  acetic  or 
nitric  acid  combines 
with  the  soda,  form- 
ing a  soluble  salt, 
which  can  easily  be 
removed  by  a  little 
subsequent  washing. 
Care  should  be  taken 
to  get  clear,  trans- 
parent acetate  of  lead.  Dr.  Vogel  recommends  the  use  of  a 
solution  of  iodine  to  remove  the  last  traces  of  hyposulphite 
from  the  washing  water.  It  is  to  be  added  and  diffused 
through  the  water  so  long  as  by  combining  with  the  hypo- 
sulphite its  color  is  destroyed.  As  soon  as  the  water  ceases 
to  discharge  the  color  of  the  iodine,  the  hyposulphite  is  elim- 
inated. We  are  not  aware  that  Dr.  VogeFs  plan  is  practiced, 
but  that  of  Mr.  Newton  is  in  actual  and  satisfactory  use. 


MEDALLION  PBINTING. 


565 


Medallion  Printing 

Is  very  effective,  and  is  now  in  general  use.  The  mode  of 
proceeding  is  as  follows  :  A  piece  of  black  paper  of  the  size 
of  the  negative  is  taken,  and  portions  of  the  size  and  shape 
of  the  desired  medallion  cut  out  of  it  as  clearly  and  evenly 
as  possible.  The  print  is  first  made  with  the  exterior  portion 
of  this,  black  paper  covering  the  exterior  of  the  negative. 
The  result  will  be  a  picture  of  an  oval  shape,  with  an  out- 
side border  of  white.  The  exterior  or  oval  portion  of  the 
black  paper  is  now  attached  to  a  piece  of  glass,  the  picture, 
already  partially  printed,  is  placed  underneath,  so  that  the 
oval  of  paper  exactly  coincides  with  the  outline  of  the  por- 
tion of  the  picture  already  printed.  Another  piece  of  glass 
is  now  placed  behind  the  print, 
and  the  two  pieces  of  glass  are 
held  in  position  by  two  clothes 
pins.  The  whole  is  now  exposed 
to  light,  and  the  outside  of  the 
paper  is  printed  as  deep  as  may 
be  desired.  Instead  of  being 
printed  plain,  the  glass  to  which 
the  oval  mark  is  attached  may 
be  a  negative  with  some  fancy 
figure  or  design  upon  it,  and 
thus  the  exterior  part  of  the  me- 
dallion picture  may  be  ornament- 
ed by  any  pleasing  design. 

A  modification  of  this  process 
is  in  the  application  of  different 
backgrounds  to  a  negative  taken 
with  a  plain  background  ;  the 
background  should  be  white  in 
order  that,  in  printing,  the  figure 
alone  should  show,  and  the  rest 
of  the  paper  remain  unchanged. 
After  the  first  print  of  the  figure  is  made,  a  second,  on  a 
small  piece  of  paper,  is  made  to  be  used  as  a  mask  while  the 
background  is  being  printed.  This  being  done,  the  mask  is 
prepared  by  cutting  off  all  portions  outside  of  the  figure. 
The  negative  of  the  background  is  now  substituted  in  the 
printing  frame  for  the  negative  of  the  figure  ;  the  first  print 
made  is  placed  upon  it,  and  the  frame  closed  as  usual.  While 
the  background  is  being  printed  upon  the  paper,  the  mask  is 
held  outside  of  the  negative  against  the  glass  and  kept 


Fig.  57. 


566  PBINTING  ON  ALBUMENIZED  PAPER. 


Fig.  59. 


Fi&-  58-  slightly  moving*  in  order  to 

avoid  printing  any  lines. 
The  making  of  these  nega- 
tives has  been  patented  by 
Messrs.  Bendann  Brothers — 
the  negatives  are  for  sale, 
and  as  are  also  the  cut  outs 
and  masks  for  the  medallion 
pictures  of  different  sizes 

Mounting. 

The  appearance  of  a  pic- 
ture is  very  much  affected 
by  its  position  upon  the 
card.  As  a  general  rule, 
the  trimming  of  the  prints 
is  left  to  boys  or  girls,  who 
have  but  little  judgment. 
One  of  our  most  successful  young  photographers,  Mr.  Frank 
E.  Pearsall,  of  Brooklyn,  practices  a  method  which  is  both 

economical  and  produces  uniform 
results.  After  his  paper  is  sil- 
vered, the  sheet  is  folded  to  a 
proper  size,  and  by  means  of  a 
drop  and  punch  a  large  number  of 
pieces  of  paper  of  exactly  equal 
size  are  cut  out  at  one  blow.  The 
position  of  the  paper  upon  the  neg- 
ative is  determined  by  the  artist 
who  retouches,  and  is  indicated  by 
a  small  piece  of  paper  cut  with  a 
recess,  forming  a  right  angle  ;  the 
piece  of  paper  to  be  printed  is  laid 
with  one  corner  fitting  into  this 
recess.  Thus  every  head  is  printed 
in  exactly  the  same  position,  and 
that  the  most  suitable  one. 

Specimen  Books. 

The  choice  of  position  or  style 
of  picture  that  may  be  desired  by 
a  sitter  can  be  determined  in  the 
office,  and  thus  save  the  time  of  the  operator  in  the  skylight. 
For  this  purpose  two  books  of  specimens  should  be  provided, 


SPECIMEN  BOOKS. 


567 


exactly  similar,  one  to  be  kept  in  the  office  for  consultation 
by  the  sitter,  and  the  other  in  the  skylight  for  reference  by 
the  operator.  The  number  of  the  sample  upon  the  order 
borne  by  the  sitter  to  the  operator  indicates  the  position  and 
style  of  picture.  Such  books  for  the  reception  of  the  samples 
are  manufactured  and  kept  constantly  for  sale  by  E.  &  H. 
T.  Anthony  &  Co. 

Among  the  aids  to  agreeable  illumination  of  the  sitter  is 
the  counter-reflector,  invented  by  Mr.  W.  Kurtz,  of  New  York. 
It  consists  of  a  screen,  composed  of  a  centre  portion  and  two 
wings.  The  wings  can  be  swung  on  their  hinges  nearer  to 
or  farther  from  the  sitter.  The  surface  toward  the  sitter  is 
white,  and  the  other  side  is  black.  The  reflector  is  placed 
between  the  camera  and  the  sitter,  and  the  negative  is  taken 
through  an  aperture  in  the  central  portion  of  the  reflector. 
This  is  a  very  useful  contrivance. 

Another  improvement  introduced  by  the  same  gentleman 
consists  in  a  moveable  platform,  upon  which  the  sitter  is 
placed  in  his  chair,  and  can  be  wheeled  to  any  part  of  the 
skylight  with  the  greatest  ease.  By  means  of  this  also,  a 
slight  change  in  position  can  be  very  readily  made  without 
altering  the  pose. 


CHAPTEE  LXVII. 


DESCRIPTION  OF  APPARATUS  ILLUSTRATED  IN 
CHAPTERS  LXI-LXVIII. 

Figure  1  is  a  representation  of  Dallmeyer's  Patent  Portrait 
Lens,  No.  3  A,  the  general  favorite  for  cabinet  portraits. 
If  you  can  only  afford  one  lens,  buy  this.  There  are  six 
sizes  of  this  mark. 

Figure  2  is  an  illustration  of  Dallmeyer's  Wide-angle 
Eectilinear,  which  embraces  an  angle  of  ninety  degrees.  Its 
absolute  rectitude  of  lines  renders  it  very  desirable  for  archi- 
tectural work,  copying,  etc.    Six  different  sizes. 

Figure  3  is  Dallmeyer's  Rapid  Rectilinear.  It  is  the  great 
group  lens.  Being  very  quick  working,  it  is  selected  for 
interiors  and  for  all  kinds  of  quick  out  door  uses.  Nine  sizes 
of  this  style. 

Figure  4  is  the  M  Success  Camera.  It  is  supplied  with 
Wright's  patent  nickel-plated  swing,  indestructible  brass 
guides,  solid  glass  corners,  etc.  This  is  the  most  useful 
of  all  cameras,  and  is  adapted  for  cartes  de  visite,  cabinets, 
and  single  portraits  on  plates  up  to  eight  by  ten  inches, 
horizontally  and  vertically.    It  is  the  gallery  box. 

Figure  5  is  the  front  view  of  an  0  Success  Camera,  fitted 
with  nine  one-ninth  lenses.  This  is  the  camera,  and  the 
only  one,  for  the  ferrotyper. 

Figure  6  is  a  rear  view  of  same  camera  as  Figure  5. 

Figure  1  is  the  new  Success  Compact  View  Box — the  light- 
est, strongest,  and  cheapest  in  the  market.  Open  and  closed 
views. 

Figure  8  is  the  Success  Stereoscopic  Camera,  Z,  for  five 
by  eight  plates.  The  ground  glass  will  be  seen  to  fold  over 
and  lie  flat  on  the  top  of  the  box.  It  is  a  beautiful  piece  of 
workmanship,  both  in  appearance  and  construction. 

Figure  9  is  one  of  the  Victoria  Cameras.  It  is  intended 
also  for  one  or  two  ferrotypes  with  one  lens,  and  four  or 
eight  with  four  lenses,  on  a  five  by  seven  plate. 

Figure  10  shows  No.  42  Gem  Box,  which  is  also  known  as 
the  New  York  Gem  Box. 


DESCRIPTION  OF  APPARATUS. 


569 


Figure  11  is  a  cut  of  our  celebrated  E.  A.  Glass  Pans,  the 
best  for  all  photographic  solutions. 

Figure  12  is  our  Glass  Bath  in  box.  This,  like  many  other 
things,  is  extensively  imitated,  which  proves  its  merit. 

Figure  13  is  the  Campbell  &  Adams  Porcelain  Printing 
Frame,  the  best  of  its  kind  for  the  purpose. 

Figure  14  is  the  Chapman  Porcelain  Printing  Frame.  It 
is  very  simple  and  practical. 

Figure  15  represents  the  Victory  Roller  Press.  It  has  no 
competition  from  other  low-priced  presses. 

Figure  16  is  a  cut  of  the  Sibley  Press,  the  best  ever  yet 
constructed  for  photographic  uses.  It  is  also  an  excellent 
burnisher. 

Figure  IT  is  a  rack  for  holding  negatives  while  drying. 
It  folds,  and  costs  but  a  trifle. 

Figure  18  is  a  Solar  Camera — the  Shive — improved  in 
working  qualities  and  convenience. 

Figure  19  is  the  Barker  Cameo  Press.  It  has  dies  of  two 
sizes. 

Figure  20  is  a  good  representation  of  the  improved  Cameo 
ress.    It  impresses  cartes  de  visite,  Victorias,  and  cabinets 
equally  well.    It  is  well  made,  and  has  several  nickel-plated 
patent  dies. 

Figure  21  is  an  engraving  of  the  best  and  most  approved 
photographic  dark  tent  we  have  ever  seen.  It  has  the  ad- 
vantage, also,  of  cheapness. 

Figure  22  is  a  pretty,  substantial  Gallery  Camera  Stand, 
for  half  size  to  eight  by  ten  cameras. 

Figure  23  is  the  most  popular  Gallery  Stand  to  be  had — 
the  Knickerbocker — with  a  top  after  Stoddard's  pattern. 
Figure  24  is  the  top  for  the  regular  Knickerbocker  Stand. 

Figure  25  is  an  Unjointed  Tripod,  simple  but  strong.  There 
are  three  sizes. 

Figure  26  is  the  square  four-post  Camera  Stand,  very  suit- 
able for  large  work.    Two  sizes. 

Figure  27  is  the  Manipulator,  a  very  convenient  contri- 
vance for  protecting  the  hands. 

Figure  28  is  a  cut  of  the  cheapest,  good  Head  Rest  in  the 
market — the  Tuscan. 

Figure  29  is  the  Bismark  Rest.    Well  adapted  for  ladies. 

Figure  30  is  the  Rigid  Head  Rest.    Stiffer  than  it  looks. 

Figure  31  is  Thornton's  Vignetting  Stand,  which  is  very 
ingenious  in  construction. 

Figure  32  represents  a  couple  of  round  cornered  Negative 
Boxes  ;  the  latest  style. 


570 


DESCBIPTION  OF  APPABATUS. 


Figure  33  is  a  plain  but  substantial  Posing  Chair,  with 
adjustable  back. 

Figure  34  is  the  Anthony  Sliding-Back  Chair,  with  arms  ; 
one  of  the  most  saleable  chairs  in  market.'   Again  improved. 

Figure  35  is  Anthony's  Revolving  Chair,  in  plush.  It  is 
strong,  and  more  inviting  than  it  looks  to  be. 

Figure  36,  Anthony's  Slidiug-Back  Chair,  without  arms. 

Figure  31  is  the  Baby  Chair.  It  has  a  little  extra  cushion, 
which  is  very  useful  for  the  small  fry. 

Figure  38  is  a  lounge  for  children  of  larger  growth.  They 
can  be  had  with  single  or  double  ends,  as  desired. 

Figure  39  is  the  Bowdish  Chair  without  rods  and  rest. 
Perhaps  the  best  and  most  suitable  chair  ever  offered  for 
photographic  use. 

Figure  40  is  a  similar  chair,  but  with  nickel-plated  rod 
and  rest  attachment.  Very  handsome  and  very  desirable  to 
many. 

;  Figure  41  represents  the  effect  produced  by  the  graduated 
background. 

Figure  42  is  Mr.  Kurtz's  Counter-Reflector.  A  very  suc- 
cessful apparatus. 

Figure  43  is  a  diagram  of  the  Baby  Charmer.  An  excel- 
lent article  for  attracting  the  attention  of  children. 

Figure  44  is  Osborne's  Steeping  Tank,  for  the  submersion 
of  old  plates  into  acid  for  cleansing, 

Figure  45  is  a  cut  of  the  improved  Retouching  Frame,  with 
reflector  and  drawer. 

Figure  46  is  the  best  gas  stove. 

Figure  41  is  one  of  the  same,  only  a  size  larger. 

Figure  48  is  still  larger. 

Figure  49,  the  ordinary  gas  stove. 

Figure  50  is  a  gas  heating  stove,  excellent  for  operating- 
rooms,  reception-rooms,  dressing-rooms,  etc. 

Figure  51  is  one  of  the  new  Gas  Ovens  for  drying  nega- 
tives and  plates.    They  are  getting  very  popular. 

Figure  52  is  a  cut  of  the  new  Cometless  Collodion  Vial. 
It  has  a  cork  covering  to  the  neck,  which  prevents  the  cap 
from  sticking,  and  diminishes  the  risk  of  breaking. 

Figure  53  is  a  Cross  Filtering  and  Pouring  Bottle,  which 
has  some  features  that  commend  it  to  every  photographer. 
It  filters  constantly  while  in  use. 

Figure  54  is  the  Philadelphia  Carte  Envelope.  It  is  very 
pretty,  and  very  largely  used. 

Figure  55  is  the  Graphoscope.    This  is  a  highly  orna- 


DESCRIPTION  OF  APPARATUS. 


571 


mental  instrument  for  the  exhibition  of  large,  single  por- 
traits and  pictures.    It  is  made  in  four  sizes. 

Figure  56  is  a  cut  of  the  Holmes  Stereoscope.  Though 
only  a  skeleton,  it  proves  to  be  the  most  perfect  instrument 
of  its  kind.  It  is  made  in  a  great  variety  of  styles,  some 
folding  up  into  a  small  compass.    (See  Figs.  60  and  61.) 

Figure  5T  is  the  ordinary  Revolving  Scope.  It  is  made  in 
imitation  rosewood  and  black  walnut,  and  holds  from  thirty- 
six  to  one  hundred  paper  views. 

No.  58  is  the  Beckers  Stereoscope.  It  is  very  elegant  and 
substantial  in  appearance,  and  is  adapted  either  for  paper  or 
transparent  views. 

No.  59  is  the  Beckers  Stereoscope  on  stand.  These  will 
hold  from  one  hundred  to  three  hundred  paper  views. 

Figure  60  is  the  New  Patent  Folding  Scope,  after  the 
Holmes  pattern,  which  folds  into  small  space. 

Figure  61  is  the  New  Patent  Folding  Scope  as  folded. 


Fig.  60. 


26 


CHAPTEE  LXVIII. 


ON  THE  EEREOTYPE  PLATE. 

As  the  business  of  making  pictures  upon  japanned  iron 
plates  is  extensive,  and  is  constantly  increasing,  it  may  not 
be  considered  out  of  place  to  occupy  a  short  space  in  giving 
some  account  of  the  present  position  of  the  industry  of  making 
the  plates. 

The  first  person  to  introduce  this  article  for  photographic 
use  was  Mr.  Peter  Neff,  of  Cincinnati.  As  some  of  the  prin- 
cipal houses  in  the  business  of  supplying  photographic  ma- 
terials were  at  that  time  largely  interested  in  the  manufac- 
ture of  daguerrotype  plates,  the  introduction  of  the  pictures 
made  by  means  of  collodion  was  strenuously  opposed  by  them. 
But  our  Mr.  E.  Anthony,  who  was  always  ready  to  encourage 
anything  which  tended  to  promote  the  interests  of  photogra- 
phy, and  who,  perceiving  the  great  importance  of  the  dis- 
covery of  the  use  of  collodion  on  the  future  of  photography, 
had  encouraged  instead  of  discouraging  it — and  who  was  at 
one  time  the  only  person  in  this  country  who  kept  and  sold 
the  materials  for  collodion  and  paper  photography  in  New 
York — having  been  requested  to  act  as  agent  for  the  sale  of 
the  "  Melainotype  Plates,"  at  once  introduced  them.  Through 
the  columns  of  Mr.  Snelling's  Photographic  and  Fine  Art 
Journal  they  were  brought  to  the  notice  of  photographers, 
and  the  sale  was  from  the  beginning  large. 

After  the  success  of  the  new  style  of  picture  was  assured, 
Mr.  V.  M.  Griswold  commenced  making  the  plates.  By  great 
devotion  to  his  business  he  finally  became  the  largest  manu- 
facturer. Years  of  application  brought  with  them  a  skill  in 
the  business  which  left  him  without  a  rival  in  the  market. 

Events  having  finally  induced  Mr.  Griswold  to  leave  manu- 
facturing, and  Mr.  John  Dean,  of  Worcester,  who  had  long 
been  engaged  in  making  other  articles  in  connection  with 
the  photographic  business,  having  commenced  the  manufac- 
ture of  the  plates,  Mr.  Griswold  sold  all  his  processes  and 
recipes  to  him.    Having  thus  succeeded  legitimately  to  the 


ON  THE  FERROTYPE  PLATE. 


573 


position  of  manufacturer  of  the  best  plates,  it  is  needless  to 
say,  in  view  of  Mr.  Dean's  established  reputation  for  excel- 
lence and  perfection  in  everything  he  makes,  that  the  Ada- 
mantean  plates  now  made  by  the  firm  of  John  Dean  &  Co.,  are 
as  near  perfection  as  possible. 

In  the  ordinary  mode  of  making  ferrotypes  the  picture, 
like  the  old  daguerreotype,  is  reversed.  Some  of  our  most 
successful  ferrotypers  now  make  them  "non-reversed."  The 
first  person  to  introduce  this  practice  was  Mr.  E.  M.  Esta- 
brooke,  of  New  York,  whose  work  upon  the  Ferrotype  is  re- 
plete with  all  the  information  necessary  for  forming  the 
expert  photographer. 


Fig.  61. 


INDEX. 


A 

Aberration,  chromatic,  84 ;  spherical,  34. 
Aberration,  to  ascertain  whether  corrected 

for  chromatic,  3T,  38,  39. 
Aberration,  to  ascertain  whether  corrected 

for  spherical,  37. 
Acetate  of  silver,  112. 

Acetate  of  soda,  104,  111,  112,  190 ;  pro- 
duces vigorous  pictures,  111. 

Aceto-nitrate  of  silver,  (formula  for,)  235, 
239,  240,  241. 

Achromatic  lenses,  40. 

Acid,  acetic,  103,  111 ;  glacial,  104 ;  checks 
reduction,  104 ;  gives  sensitiveness,  104. 

Acid,  citric,  preparation  of,  105, 106 ;  uses 
of,  107. 

Acids,  in  developing  solutions,  102 ;  as  re- 
tarders  of  development,  102, 103. 

Acid,  formic,  a  reducing  agent,  95 ;  prepar- 
ation of,  104 ;  photographic  uses  of, 
105 ;  used  as  developer,  169. 

Acid,  gallic,  a  reducing  agent,  95 ;  symbol 
of.  99;  preparation  of,  100;  a  devel- 
oper, 237,  239. 

Acid,  hydriodic,  preparation  of,  70. 

Acid,  hydrobromic,  preparation  of,  76. 

Acid,  hydrocyanic,  (prussic,)  preparation 
of,  119. 

Acid,  hydrosulphocyanic,  preparation  of, 
120. 

Acid,  metagallic,  101. 

Acid,  nitric,  a  reducing  agent,  95. 

Acid,  phosphoric,  806. 

Acid,  pyrogallic,  a  reducing  agent,  95; 
symbol  of,  99 ;  preparation  of,  101 ; 
a  developer,  146:  an  intensifier,  148. 

Acid,  tannic,  a  reducing  agent,  95 ;  prepar- 
ation of,  99 ;  uses  of,  100 ;  vide  Tannin 
Process,  245 ;  a  developer,  247,  249. 

Acid,  tartaric,  preparation  of,  107;  a  re- 
tarder  of  reduction,  103 ;  printing  with, 
285. 

Actinic  focus,  coincidence  with  luminous, 

39. 

Affinity  of  metals,  95. 

Aguillon,  Francis,  312. 

Alabastrine  positives,  140;  alabastrine  so- 
lutions, 140. 

Albumen,  preparation  of,  194 ;  formulas  for 
iodized  albumen,  238,  239,  240,  241, 
243;  albumen-process,  238;  collodio- 
albumen-process,  237,  241 ;  and  bi- 
chromate of  potassa,  299  ;  and  bichro- 
mate of  ammonia,  308. 

Albumenized  paper,  preparation  of,  194. 


Alcohol,  hydrated  oxide  of  ethyle,  56 ;  pre* 
paration  of  ether  from,  58;  prepara- 
tion of,  59,  60. 

Alcoholic  collodion,  19. 

Aldehyde,  111. 

Amber  varnish,  with  chloroform,  137 ;  with 
benzole,  137. 

Ambrotype,  23 ;  how  to  make,  128  to  140. 

Ammonia,  197 ;  bichromate  of,  308. 

Ammonium,  symbol  and  combining  propor- 
tion, 71 ;  chloride  of,  191 ;  iodide  of, 
73;  sulphide  of,  125. 

Ammoni-nitrate  of  silver,  formula  for  bath, 
197 ;  albuminous  film  not  injured  by. 
198. 

Angle,  parallactic,  313. 

Aperture  angular,  defined,  40. 

Aperture,  (of  diaphragm,)  relation  between, 

and  opening  of  the  lens,  41. 
Apertures  in  the  collodion  film,  112 ;  cause 

and  remedy,  328,  329. 
Apothecary's  weight,  339. 
Aplanatic  lenses,  40. 

Aqua-tinta  granulation,  289;  application 
of,  294,  295. 

Arago,  report  of,  to  the  Chamber  of  Depu- 
ties, 13. 

Arcken,  first  application  of  gun-cotton  by, 
19 ;  and  Pry  published  a  detailed  ac- 
count of  gun-cotton,  51. 

Arrowroot  papers,  preparation  of,  195. 

Asser,  used  transfer  process,  21. 

Asphaltum  in  chloroform,  21 ;  for  black  var- 
nish, 138 ;  dissolves  in  benzine,  291 ; 
properties  of,  298. 

Asphaltotype  of  Nicephore  Niepce,  291. 

Asphalto-photolithographic  process,  297. 

Astronomical  photographers,  320;  Society 
confer  medal  on  De  la  Rue,  322. 

Axis,  convergence  of,  314. 

Avoidupois  weight,  338. 


B 

Background,  illustration  of,  30;  variour 
plain,  graduated,  pictorial,  31;  color- 
ing of,  230. 

Bath,  vertical,  horizontal,  109,  110;  glass, 
porcelain  photographic  ware,  109 ;  pre- 
paration of  the  sensitizing  solutions  for 
collodion  pictures,  110,  111 ;  with  ace- 
tate of  soda  and  acetic  acid,  111 ;  for 
summer,  111;  how  to  restore  when 
weak,  111 ;  how  to  treat  the  bath  when 
acid  or  alkaline,  112, 113 ;  the  necessity 


INDEX. 


of  filtering,  113;  to  add  tincture  of 
iodine  to  the  collodion  in  order  to  pro- 
duce acidity  in,  112 ;  take  care  that  no 
actinic  rays  get  to,130 ;  for  paper,  196 ; 
ammonio-nitrate,  197 ;  for  toning,  202. 

Barium,  symbol  and  equivalent,  71 ;  iodide 
of,  71 ;  chloride  of,  191. 

Barreswil,  attempts  photolithography  first, 
298. 

Beauregard,  Testud  de,  process,  276. 
Beaume,  342. 

Becquerel  on  heliochromy,  323. 

Benzine,  how  to  render  anhydrous,  291,  293. 

Benzoin,  209. 

Berard's  experiments  with  the  spectrum,  12. 
Berry,  321. 

Bertrand's  new  process  for  positive  print- 
ing, 209. 
Biology,  10. 

Bichromate  of  potassa,  11,  276,  277,  280; 
bichromate  of  ammonia,  278,  808. 

Bichromo-photo-lithographic  processes,  299. 

Bichloride  of  mercury,  as  developer,  275 ; 
as  intensifier,  169  ;  preparation  of,  125. 

Bitumen  of  Judea,  first  used  by  Niepce,  14. 

Blanchard's  (Valentine)  instantaneous  pro- 
cess, 169 ;  prefers  bromo-iodized  collo- 
dion, 168  ;  strengthened  with  bichlo- 
ride of  mercury,  169. 

Blanquart  Evrard's  intensifying  process 
by  a  second  exposure  to  light,  124; 
bromo-iodizing  solutions  for  printing  by 
development,  263 ;  sensitizing  bath  and 
development,  264. 

Blonde  hair,  coloring  of,  227. 

Black  hair,  coloring  of,  227. 

Blue  drapery,  coloring  of,  227. 

Blue-tone,  owing  to  excess  of  toning,  or  to 
acid  toning,  335. 

Boiled  oil,  in  transfer  varnish,  151. 

Bond,  Messrs.,  820. 

Brewster,  refracting  stereoscope,  312. 

Bromides,  65 ;  bromide  of  silver  sensitive 
to  certain  colors,  66;  bromide  of  sil- 
ver, 91. 

Bromine,  75 ;  preparation  of,  75. 

Bromo-iodized  collodion,  greater  capacity 
for  colors,  66,  67. 

Bromo-iodizing  solution  for  printing  by  de- 
velopment, 263. 

Bronzing,  334. 

C 

Cadmium,  symbol,  combining  proportions, 
specific  gravity,  71 ;  iodide  of,  67,  73. 

Calcium,  symbol,  combining  properties, 
specific  gravity,  71 ;  iodide  of,  72. 

Calotype,  discovery  of,  17, 18 ;  how  to  sen- 
sitize, 171 ;  Prichard's  process,  180 ; 
Geoffray's  process,  178;  Tillard's  pro- 
cess, 180.   (Vide  Talbotype.) 

Camera,  34,  42 ;  invention  of,  42 ;  must  be 
horizontal  for  architectural  purposes, 
43 ;  stereoscopic,  164 ,  If  tilted,  how  to 
rectify  the  error,  164  *  where  to  place, 
165;  camera  stand,  165. 

Camarsac,  Lafon  de,  276. 

CamePs-hair  pencil.  225. 

Camphene,  Li  transfer  paper,  151. 

Canada  balsam,  in  varnish,  150 ;  for  black 
varnish,  188. 


Cap,  used  as  an  instantaneous  shutter,  1T0. 

Carbon,  reducing  agent,  94 ;  lampblack  in 
black  varnish,  138;  in  Fargier's  pro- 
cess, 280 ;  in  Poitevin's,  281  •  as  ivory 
black  in  Salmon  and  Garnier's  process, 
279 ;  in  Pouncy's  process,  277 ;  print- 
ing, 20 ;  process,  275 ;  processes  with 
the  salts  of  iron,  281;  print,  how  to 
transfer,  283. 

Carbonate  of  lime,  preparation  of,  190 ;  in 
toning  formulas,  (chalk,)  202. 

Carbonate  of  soda,  preparation  of,  190 ;  in 
toning  formulas^  202. 

Card-picture,  218;  coloring  of,  224. 

Celestial  photography,  820. 

Cerolein,  178, 179. 

Centigrade  scale,  340, 841. 

Chaldeans,  10. 

Champlouis,  (De,)  improvement  in  the  wax- 
paper  process,  176. 
Chardon,  276. 

Chemical  equivalents,  table  of,  844. 

Chestnut-colored  hair,  227. 

Chimenti's  drawings  not  stereoscopic,  318. 

Chinese  vermilion,  225 ;  Chinese  white,  225. 

Chlorides,  76;  of  lime,  78;  chlorinetted 
lime,  78;  of  gold,  187,  203;  of  silver, 
photographic  properties  of,  93;  of  sil- 
ver used  for  dry-plating  and  galvano- 
plasty,  93 ;  of  silver,  12. 17. 

Chloroform,  solvent  of  varnish,  137, 189 ;  in 
black  japan,  150. 

Chromotype,  22. 

Citrate  of  iron,  279 ;  of  soda,  106, 190. 

Citric  acid,  105 ;  uses  of,  106. 

Clarifying  operation  of  negatives,  154. 

Claudet's  developer,  169. 

Cleaning  and  polishing  the  silver  plate,  (Da- 
guerreotype,) 268 ;  the  surface  of  the 
photo-lithographic  print. 

Clippings  of  prints,  207. 

Coating  the  glass,  (wet  process,)  129 ;  the 
paper  with  the  sensitive  solution  photo- 
lithography, 304. 

Collodion,  19;  decomposition  of,  61,  62; 
least  stable,  64 ;  most  permanent,  64 ; 
sensitizers,  65 ;  for  tannin  plates,  246 ; 
plain  or  normal,  79 ;  iodized,  79  ;  bro- 
mo-iodized, 79,  80;  Wortley's,  Lieut.  - 
Col.  Stuart,  formula  of,  80;  Omme- 
ganck's  formula  of,  81 ;  Disderi's  for- 
mulas of,  81 ,  82,  83  ;  wet  process,  127 ; 
positives,  127, 136 ;  negatives,  144 ;  pos- 
itives on  glass,  153 ;  dry-process,  232 ; 
collodio-albumen  process,  237,  241 ;  for 
Taupenot  plates,  238 ;  formula  of  Col. 
Sir  H.  James,  303 ;  imperfections  of  nega- 
tives, 326 ;  remedies  of,  826,  etc. 

Coloring,  of  collodion  positives,  136 ;  of  a 
card-picture,  224 ;  of  a  portrait,  225 ; 
of  the  face,  226,  228,  229. 

Colors,  not  rendered  permanent  in  helio- 
chromy, 323. 

Comparison  of  hydrometric  indications, 
504 ;  of  weights  and  measures,  499  ;  of 
thermometric  indications,  502. 

Condensers,  157. 

Contrast  of  light  and  shade,  127 ;  excess  of, 

cause  of,  322  ;  deficiency  of,  321. 
Copal,  soft  varnish,  157 ;  with  benzole,  187. 
Copies,  for  the  engraver  to  work  from,  296. 
Copying  of  collodion  negatives  or  posi- 


INDEX. 


tires,  160, 161, 162 ;  of  any  given  size, 
263. 
Copernicus,  10. 

Copper,  requires  a  strong  etching  fluid, 

296. 

Corrosive  sublimate,  125. 
Crookes,  320. 
Crysotype,  2T3. 

Crystalline  lens,  moved  by  ciliary  muscle, 
311. 

Cyanide  of  potassium,  119, 120, 155 ;  a  re- 
ducing agent,  121. 
Cyanogen,  118 ;  preparation  of,  118. 
Cyanotype,  273. 

D 

Davanne,  298. 

David  Hilaire,  231. 

Daguerre,  13, 14, 15, 16. 

Daguerreotype,  268 ;  latent  image  brought 
out  by  mercury,  15,  270. 

Dark-room,  46,  47 ;  what  it  contains,  47,  48. 

Defects,  in  the  printing  of  negatives,  333 ; 
in  the  paper,  333;  defective  sensitiz- 
ing, 333;  defective  toning,  334;  defec- 
tive fixing,  335. 

Deficiency  of  contrast  in  the  negative,  cause 
of,  331. 

Definition,  imperfect,  cause  of,  832. 

Developers,  94;  negative,  145,  146;  sul- 
phate of  iron,  114, 115 ;  DisderPs,  115 ; 
Lieut.-Col.  Stuart  Wortley's,  116, 168 ; 
Meynier's,  116;  Hockins's,  116,:  169; 
Waldack's,  116,  117;  Claudet's,  169; 
Crookes's,  177 ;  De  Champlouis's,  177 ; 
too  intense,  cause  of  fogging,  328. 

Developing,  solutions,  114,  213;  the  pic- 
ture, (wet  process,)  131,  132;  Fother- 
gill's,  243;  Col.  Sir  H.  James's,  303; 
of  the  silver  plate,  270. 

Development,  of  the  card-picture,  219 ;  of 
the  albumen  film,  287';  of  the  Taupe- 
not  plates,  239 :  of  the  tannin  plates, 
247,  248. 

Diffused  light,  in  the  camera,  cause  of  fog- 
ging, 326 ;  in  the  dark-room,  etc.,  cause 
of  fogging,  828. 

Direct  rays  of  the  sun  through  the  axis  of 
the  lens,  cause  of  fogging,  327. 

Distances,  long  and  short,  seen  at  the  same 
time,  310,  312 ;  theories  about,  311 ;  dif- 
ferences of,  313. 

Distillation  of  the  nitrate-bath,  112. 

Distortion,  from  too  great  contrast  of  light, 
27. 

Dolland,  9. 

Doublet,  35. 

Donne,  287. 

Draper,  Dr.,  use  of  hot  water  in  the  tannin 

process,  248. 
Drying  the  positive  plate,  (wet-process,)  135. 
Drying  process,  of  albumen  films,  235. 


E 

Eclipses,  photographed,  822. 
Edwards,  821. 
Electric  telegraph,  10. 
Electricity,  a  reducing  agent,  95. 
Elements  of  matter,  table  of,  506. 


Enamels,  how  to  make,  309. 

England,  formula  for  collodion  for  the  tan 

nin  process,  249. 
Engraving,  photographic,  286 ;  heliographic, 

296 ;  on  the  daguerreotype  plate,  286. 

290. 

Etching,  fluid,  289,  290 ;  of  the  plate,  295 ; 
on  glass,  296 ;  on  zinc,  306. 

Ether,  55 ;  how  to  prepare,  58 ;  property  of, 
on  collodion,  61. 

Ethyle  group,  55. 

Eureka  plate,  140. 

Excelsior  plate,  140. 

Exposing  the  glass,  (wet  process),  131. 

Exposure  of  the  silver  plate,  (Daguerreo- 
type,) 269;  photo-engraving,  293;  un- 
der the  negative,  (photo-lithography,) 

Eye,  its  philosophy,  811 ;  single  eye  cogni- 
zant of  relief,  311. 


F 

Fahrenheit,  scale,  840,  341. 
Fargier,  275. 

Feebleness  of  the  negative  image,  cause  ot 

331. 
Ferrier,  119. 

Ferreotype  plates,  ajpt  to  blister  in  the  dry- 
ing, 143. 

Field  photography,  rules  to  be  observed,  44. 

Films,  tender  and  rotten,  cause  of,  832. 

Fixation  of  the  Taupenot  plates,  239. 

Fixing,  solutions,  118,  121 ;  the  picture, 
(positive  —  wet  process,)  133;  solu- 
tions for  negatives,  147 ;  solutions  for 
prints,  203 ;  of  the  card-picture,  221 ; 
of  the  image,  (Daguerreotype,)  270. 

Fizeau,  16. 

Flowing  the  varnish,  in  photo-engraving, 
292. 

Focus,  of  a  lens,  (how  to  find,)  36,  43,  44; 
equidistant  conjugate,  36,  254,  255; 
principal,  254 ;  equivalent,  254 ;  actinic 
and  luminous,  (coincidence  of,)  39. 

Fogginess,  remedy  for,  134,  326,  327,  328. 

Fogging,  111. 

Formic  acic,  a  reducing  agent,  95. 
Forrest,  321. 

Formula  for  zinc  enamel,  807. 

Fothergill  process,  242. 

French  government,  16. 

Fumes  of  ammonia,  cause  of  fogging,  828. 

Fumigation  of  the  asphaltum  film,  294. 

Eliminating,  apparatus,  199 ;  process,  198.  j 


G 

Gallic  acid,  a  reducing  agent,  95 ;  prepara- 
tion of,  100. 
Gallo-nitrate  of  silver,  17. 
Galls,  Aleppo,  306. 
Gamier,  275. 

Gelatine,  185;  operation,  (tannin-process,) 

245 ;  process,  244. 
Geoffray,  process  with  cerolein,  178. 
Glass,  actinic,  32;  non-actinic,  46;  house, 

28,  29 ;  plates,  (preparation  for  Taupe* 

not  plates,)  238;  vignette,  223;  how 

to  clean,  303. 


INDEX, 


Globe  leng,  165. 

Glover'3  resinized  printing  process,  210. 
Glycyrrhizlne,  makes  collodion  sensitive. 
63. 

Gold,  deposited  by  galvanism,  287 ;  chlo- 
ride of,  187,  203 ;  gold  and  uranium 
toning,  202. 

Grain,  engravers,  298. 

Gramme,  337. 

Granulation,  Aqua-tinta,  (how  made,)  289  ; 

application  of,  294. 
Grape-sugar,  makes  collodion  sensitive,  63. 
Gray  hair,  how  to  color,  228. 
Green  drapery,  229. 

Gum,  arabic,  187;  guaicum,  12;  mastic, 
210 ;  thus,  210 ;  sandarac,  varnish  for 
cold  plate,  139. 

Gutta-percha  baths,  cause  of  fogging,  328. 


H 

Hardwick's  views  about  the  decomposition 

of  collodion,  62,  63. 
Harshness,  or  excess  of  contrast,  cause  of, 

332. 

Harrison,  C.  C,  41 ;  Globe  lens,  165. 

Hartnup,  321. 

Heat,  a  reducing  agent,  95. 

Heliochromy,  22 ;  or  the  art  of  taking  pho- 
tographs in  their  natural  colors,  323. 

Heliography,  11,  14;  heliographic  engrav- 
ing, Negre's  process,  296. 

Herschel,  Sir  John,  15, 18,  323. 

Hipparchus,  10. 

History  of  photography,  9. 

Hockins,  Developer,  116, 169. 

Hodgson,  821. 

Hoffmeister,  131. 

Holmes,  Booth  and  Hayden's,  41. 
Honey,  308. 
Horn  silver,  92. 

How  to  improve  the  color  of  transparent 
positives^  253. 

How  to  take  diminished  copies  of  photo- 
graphs, 265. 

How  to  take  enlarged  copies  of  photographs, 
262. 

How  to  transfer  the  carbon  print  from  glass 

to  paper,  283. 
Hydriodic  acid,  70. 
Hydrobromic  acid,  76. 
Hydrocyanic  acid,  119. 
Hydrogen,  a  reducing  agent,  94. 
Hydrometers,  842. 
Hydrosulphocyanic  acid,  120. 
Hyposulphite  of  soda,  120, 121. 


I 

Illumination,  for  copying  different  from 
that  in  portraiture,  162, 163. 

Image,  imperfections,  theory  of,  325. 

Image,  solid,  314,  315. 

Imperfections,  in  collodion  negatives  and 
their  remedies,  326,  etc. ;  fogginess,  326, 
in  paper  prints,  383 ;  in  albumenizing 
and  salting,  333 ;  washing  previous  to 
toning,  334. 

India-rubber  for  black  varnish,  138. 

Inking,  of  the  bichromate  print,  304 


Instantaneous  process  of  Lieut. -CoL  Stu- 
art Wortley,  167 ;  shutters,  169 ;  stere* 
ographs,  166. 

Intensifies,  122,  147,  168,  242;  Sir  H. 
James's  302 

Intensifying'  first  method,  147,  148,  123 ; 
second  and  third  do.,  124. 

Iodides,  65 ;  alkaline  all  soluble,  65 ;  testa 
of  purity,  74 ;  preparation  of,  69 ;  im- 
purities of,  73. 

Iodide,  of  potassium,  not  very  soluble,  65 ; 
of  ammonium,  easily  decomposed,  65 ; 
of  silver,  sensitive  to  certain  colors, 
65;  of  cadmium,  glutinizes  collodion, 
67 ;  alkaline,  liquefies  collodion,  67 ; 
of  barium,  71 ;  of  calcium,  72 ;  of  lith- 
ium, 72 ;  of  potassium,  72 ;  of  sodium, 
73 ;  of  ammonium,  73. 

Iodine,  69 ;  of  cadmium,  73 ;  of  silver,  pre- 
paration of,  90;  properties  and  tests 
of,  70. 

Iodizers,  certain  ones,  cause  of  fogging,  327. 

Iodized  albumen,  233,  234,  240,  241. 

Iodizing  for  gelatine,  tannin  process,  246 ; 
of  wax  paper,  174. 

Iron,  developer  for  negatives,  145, 146 ;  sul- 
phide of,  98 ;  protosalts  and  persalts  of. 
97, 98.  * 

J 

James,  Col.  Sir  Henry,  21,  801,  308. 
Japan,  black,  150. 

Joubert's  process  for  taking  photographs  on 

glass  in  enamel  colors,  308. 
Jupiter  and  his  bands  photographed,  322. 


K 

Keene's  Rapid  dry  process,  250. 
Kaiserstuhl,  11. 


Ii 

Lace,  how  to  imitate  in  colors,  231. 
Lampblack,  for  black  varnish,  138. 
Landscape,  photography,  164. 
Lavender,  oil  of,  11. 

Legray,  wax-paper  process,  173 ;  first  sug- 
gested the  use  of  gun-cotton,  51. 

Lens,  34 ;  crossed,  34 ;  how  to  buy  a  good  one, 
39 ;  single  equivalent  to  a  compound,  87 ; 
axis  of,  254;  optical  centre  of,  254  • 
principal  focus  of,  254 ;  conjugate  foci 
of,  254 ;  equivalent  focus  of,  254 ;  equi- 
distant conjugate  focus,  224 ;  vertex  of, 
254;  how  to  find  the  principal  focal 
distance  of,  254 ;  how  to  find  where  the 
lens  is  to  be  placed  in  the  solar  micro- 
scope, 260. 

Lenses,  for  the  card-picture,  219 ;  compara- 
tive value,  36 ;  magnifying  power,  37 , 
Harrison's,  Ross's,  Dallmeyer'SjGrubb's, 
Jamin*s,  Holmes's,  Booth  and  Hayden's, 
Voightlaender's,  41. 

Lerebours,  298. 

Light,  action  of,  96 ;  a  reducing  agent,  95 ; 

single,  162 ;  velocity  of,  102 ;  must  entel 

from  the  north. 
Lime,  carbonate  of,  190. 


INDEX. 


Linseed  oil,  rubbed  into  an  engraved  plate, 
28T. 

List  of  a  photographic  outfit,  25,  26. 
Lithium,  Tl ;  iodide  of,  72. 
Litre,  33T. 
Lunar  caustic,  88. 

M 

Macrophotography,  257,  262. 
Manipulation,  of  positive  printing,  192. 
Marbled  appearances  in  the  paper,  833. 
Marion's,  Preserving  box,  210. 
Mars,  photographed,  322. 
Mats,  139. 

Matter  for  the  reception  of  the  image,  23. 

Materials  used  in  positive  printing,  183. 

Mayo's  Outlines  of  Human  Physiology,  312. 

Mealiness,  on  the  print,  336. 

Melainotype,  23 ;  plate,  apt  to  blister  in  the 
drying,  143. 

Mercury,  bichloride  of,  125 ;  vapor  of  a  de- 
veloper, 15,  270 ;  preparation  of,  bichlo- 
ride of,  125 ;  bichloride  of,  an  intensi- 
fies 169 ;  developer,  275. 

Metals,  how  to  imitate  in  colors,  230. 

Metre,  337. 

Modified  albumen  process,  240. 

Modified  collodio-albumen  process,  (James 

Mudd's,)  241. 
Monckhoven,  (Van,)  272;  his  views  about 

the  decomposition  of  collodion,  61,  62. 
Moon,  photographed,  321;  stereographed, 


N 

Negatives,  for  enlargement,  262;  for  card- 
pictures,  221;  collodion,  144;  enlarge- 
ment by  the  camera,  157;  on  paper, 
171;  definition  of,  24;  developer  for, 
145, 146. 

Negre's  process,  296. 

Newton's,  photo-lithographic  process,  300. 
Nicephore  Niepce,  asphaltotype,  291,  297. 
Niepce,  14,  15, 16. 
Niepce,  Isidore,  16. 

Niepce  de  St.  Victor,  18,  22,  233 ;  on  helio- 

chomy,  323. 
Nitrate  of  silver,  photographic  properties 

of,  88,  89 ;  bath,  109,  110,  111 ;  cause 

of  fogginess,  327. 
Nitric  acid,  a  reducing  agent,  95. 
Nitro-glucose,  preparation  of,  63. 
Non-azotized  substances,  186. 
Norris,  Dr.  Hill,  process,  244. 


O 

Oil,  of  bergamot,  in  varnish,  149 ;  of  laven- 
der, 21. 

Ommeganck's  formula  for  collodion,  81. 

Osborne,  20. 

Ounce,  avoirdupois,  100 ;  Troy,  100. 
Over-development,  cause  of  fogging,  334. 
Oxide  of  silver,  how  to  prepare,  110. 


P 

Paper,  alburaenieed,  194 ;  arrowroot,  195 ; 


for  transfer-process  in  photo-litlio* 
graphy,  304. 

Pearl-gray,  color,  230. 

Pension,  16. 

Persalts  of  iron,  97,  98. 

Phosgene  gas,  13. 

Phosphate  of  soda,  190. 

Photographic-ware  baths,  110. 

Photography,  11 ;  Celestial,  320 ;  photo- 
graphic engraving,  286. 

Photographs,  mounting  of,  205,  206 ;  photo- 
graphic properties  of  chloride  of  silver, 
93. 

Photo-lithography,  297 ;  asphalto- photo-lith- 
ographic process,  297  ;  photo-zinco- 
graphy, 297;  first  attempts  at,  297; 
Newton's  process,  300  ;  Osborne's,  301 ; 
Col.  Sir  H.  James's,  301;  photo-typo- 
graphic process,  300 ;  photo-lithograph 
ic  ink,  304 ;  photo-papyrography,  308. 

Physiology,  10. 

Pink  drapery,  229. 

Pictures,  red,  green,  violet,  blue,  274,  275. 

Ponton  Mungo,  19. 

Poitevin,  20,  21,  270,  299,  300. 

Porta,  42 ;  Giovanni  Battista  Delia,  312. 

Positive,  printing  on  paper,  182  ;  transpar 

ent  by  contact,  159. 
Positives,  collodion,  127 ;  alabastrine,  140 ; 
Potassium,  71 ;   cyanide  of,  119 ;  sulpho- 

cyanide  of,  120 ;  sulphide  of,  125  ;  iodide 

of,  72. 

Preliminary  observations,  23. 

Preparation,  of  salted  paper,  192;  of  the 
plates  of  steel,  etc.,  for  photo-engrav- 
ing ;  of  the  glass ;  wet  collodion  process, 
128, 129. 

Preservers,  139  ;  preservative,  solution,  Dr. 
Hill  Norris,  244 ;  tannin  plates,  247. 

Printing,  of  sensitized  paper,  200 ;  without 
the  salts  of  silver,  272 ;  with  the  chlo- 
ride of  silver,  191 ;  by  development, 
212 ;  directly  on  paper  by  means  of 
the  sesqui-chloride  of  iron  and  tartaric 
acid,  285 ;  of  card-pictures,  222  ;  direct, 
182;  transparent  by  contact,  159; 
transparent  by  the  dry-process,  252. 

Process,  Pouncy's  carbon,  277  ;  Salmon  and 
Garnier's  carbon,  278 ;  Fargier's  carbon, 
275,  280 ;  carbon  with  the  salts  of  iron, 
281;  for  colored  pictures,  274,  275; 
albumen,  233 ;  dry  collodion,  232 ; 
Humbert  de  Molard,  ISO ;  Prichard's 
Calotype,  180;  Talbotype,  172;  wax- 
paper,  173;  Geoffray's,  178;  Tillard's, 
179;  Niepce  de  St.  Victor,  216;  Fumi- 
nating,  198;  Resin,  249;  Rapid  dry, 
250;  Bertrand's,  209;  Glover's,  210; 
drying  of  albumen  films,  235 ;  Fother- 
gill's,  242 ;  Taupenot's,  237 ;  Dr.  Hill 
Norris's,  244  ;  Tannin,  245 ;  Tannin  and 
Honey,  248 ;  Fizeau's,  (similar  to  that 
of  Donne,)  287  ;  Negre's,  296 ;  asphalto- 
photo-lithographic,  297  ;  bichromo-pho- 
to-lithographic,  299 ;  photo-typographic, 
300;  Newton's,  (photo-lithographic,) 
300  ;  Joubert's  (colored  enamel,  30S. 

Prussic  acid,  119. 

Pyrogallic  acid,  a  reducing  agent,  95 ;  pre- 
paration of,  101 ;  developers,  115, 146. 

Pyroxylinc,  51 ;  preparation  of,  52,  63  ;  foi* 
mulas  for  making,  53,  54,  55. 


INDEX. 


Q 

Quality  of  the  paper  used  in  the  transfer 
process. 

B 

Radiant,  axis  of,  254. 

Rapid  dry  process,  250. 

Rays,  direct  and  parallel,  159. 

Reaumur's  scale,  340,  341. 

Red,  hair,  (coloring  of,)  227 ;  tone  owing  to 
defective  toning,  334 ;  drapery,  (color- 
ing of,)  229. 

Redeveloping  process,  147. 

Reflections  within  the  camera,  cause  of  fog- 
ging, 326. 

Reflectors,  used  as  condensers,  157. 

Resin  process,  249. 

Retina  of  the  eye,  not  a  surface,  810. 

Rice  water,  174. 

Ridges  and  undulating  lines  In  the  negative, 

330. 
Ritter,  12. 

Rose-colored  drapery,  (coloring  of,)  229. 

Roulette,  9. 

Royal  Society,  15, 16. 

Rue,  (De  la,)  321,  322. 

Russell,  (Major,)  245. 


S 

Salmon,  275 ;  Salmon  and  Garnier's  carbon 
process,  278. 

Salted  paper,  (formulas  for,)  192. 

Salting  solutions,  (for  printing  by  develop- 
ment,) 212,  213. 

Salts  of  iron,  (printing  with,)  273;  in  carbon 
processes,  281;  of  uranium,  printing 
with,  273. 

Saturn  and  his  rings,  photographed,  322. 
Scale,  thermometric,  340,  341. 
Scheele,  12. 

Scott,  Captain,  improvements  in  photo-litho- 
graphy, 301. 

Screens,  31 ;  with  graduated  tints,  31 ;  pic- 
torial, 31. 

Seebeck,  12. 

Self-acting  washing  machine,  205. 

Sensitizing,  solution,  (James  Mudd's,)  241 ; 
solution,  (James  Larpey's,)  240;  of 
Taupenot's  plates,  239 ;  of  the  albumen- 
film,  235;  substances,  24;  (nitrate  of 
silver,)  110,  111 ;  the  collodion  film,  (wet 
process,)  130;  (nitrate  of  uranium,) 
216,  217;  defective,  833;  plain  silver 
bath,  196 ;  ammonio-nitrate  bath,  197 ; 
for  development,  214,  215,  216;  the 
daguerreotype  plate,  269 ;  of  wax- 
paper,  175. 

Sesquichloride  of  iron,  285 ;  formula  of,  in 

carbon  process,  281. 
Side-light,  29. 

Silver,  oxide  of.  110;  iodide  of,  90,  110; 
chloride  of,  92,  191 ;  salts,  84 ;  reduc- 
tion of,  85,  86,  87 ;  nitrate  of,  88 ;  pho- 
tographic properties  of  the  nitrate  of, 
88,  89;  hyposulphite  of,  90;  sulphate 
of,  90 ;  bromide  of,  91 ;  tests  of  the  chlor- 
ide of,  93  ;  photographic  properties  of 
the  chloride,  98. 


Sir  Humphry  Davy,  13. 
Soda,  citrate  of,  106,  190 ;  hyposulphite  of, 
120 ;  acetate  of,  190 ;  phosphate  of,  190. 
Sodium,  71 ;  chloride  of.  191 ;  iodide  of,  73. 
Solarization,  cause  of,  332. 
Soleil  and  Dubosc,  312. 
Solution  for  transfer  paper,  151. 
Solvent,  of  the  asphaltum  film,  293. 
Specialties,  27. 

Specific  gravity,  comparison  of,  842. 
Spectrum,  12. 

Spots  and  apertures  in  the  negative,  328, 
329  ;  opaque,  329  ;  transparent,  329, 830. 
Starch,  186. 
Steam-engine?  10. 

Stereograph,  instantaneous,  116, 167 ;  stereo- 
graphic  negatives,  164;  strabonic,  314, 
815 ;  how  to  see  strabonic  stereographs, 
816,317;  Towler's,  319. 

Stereoscope,  Wheatstone's,  312 ;  mere  optical 
contrivance,  315. 

Stereoscopicity,  theory  of,  310. 

Stone,  for  photo-engraving,  298,  299. 

Streaks  and  stains,  cause  and  remedy,  881. 

Sugar  of  milk,  Legray's  formula,  174. 

Suitable  rooms,  27. 

Sulphate  (double)  of  ammonia  andiron,  98; 
sulphate  of  silver,  90. 

Sulphide  of  iron,  98 ;  of  potassium,  (prepara- 
tion of,)  125;  of  ammonium,  125. 

Sulphocyanide  of  potassium,  120;  of  ammo* 
riium,  120. 

Sulphovinic  acid,  58. 

Sulphurous  acid,  58. 

Sulphuric  acid,  58. 

Sun,  easily  photographed,  321. 

Sutton,  19 ;  rapid  dry  process,  250. 

Symbols  of  elementary  bodies,  844. 


T 

Table  for  increasing  or  diminishing  the  size 
of  a  picture,  256. 

Talbot  Fox,  16, 17,  21. 

Talbotype,  17, 171 ;  process,  172. 

Tannic  acid,  a  reducing  agent,  95 ;  prepara- 
tion of,  99. 

Tannin  process,  245;  and  honey  process, 
248 ;  preservative,  249. 

Tartaric  acid,  preparation  of,  107 ;  printing 
with,  285. 

Taupenot  process,  237. 

Temperature  modifies  development,  103. 

Telescopes,  reflecting  and  refracting,  320. 

Tillard,  turpentine  and  wax  process,  179. 

Toning  of  prints,  201;  formulas,  202;  of 
card-pictures,  224 ;  first  effect  of,  204 ; 
of  the  silver  plate,  (daguerreotype,)  271. 

Transfer  paper,  20,  151 ;  process,  of  collo- 
dion pictures,  150 ;  ink,  307 ;  solution, 
151;  of  carbon  print  from  glass  to 
paper,  283. 

Transference  of  the  print  to  zinc  or  stone, 
305. 

Transparent  positives,  153,  159,  285,  289* 

by  the  dry  process,  252. 
Triplet,  35. 

Turpentine,  in  transfer  solution,  151. 
Twaddell's  hydrometer,  842,  848. 
Tyrolese  Alps,  11. 


INDEX. 


U 

Under-exposure,  the  causa  of  fogging,  334. 
Unit,  English  linear,  French  linear,  337. 
Undulating  lines  on  the  negative,  330. 
Uranium,  printing  with,  273 ;  and  gold  ton- 
ing, 202 ;  nitrate  of,  189. 


V 

Varnish  of  Niepce  de  St.  Victor,  291 ;  for 
collodion  pictures,  137, 139 ;  black,  138, 
139  ;  applied  cold,  139. 

Varnishing  of  collodion  positives,  136. 

Vergennes,  formula  of,  256. 

Vicar  of  Wakefield,  32. 

Vignette-printing,  223. 

Vinci,  Leonardo  da,  on  binocular  vision,  811. 

Violet  color,  230 ;  colored  glass  for  focussing 
actinically,  39. 

Virtual  solid  image,  314. 

Vision,  binocular,  812. 


W 

Waldack's  developers,  116, 117. 
Washing  machine,  (self-acting,)  205 ;  of  the 
solvent,  (asphaltotype,)  294 


Watt,  9. 

Wax-paper  process,  173. 

Wedgwood,  13,  14. 

Weight  of  water,  62,  338. 

Weights,  apothecaries  and  avoirdupois,  500; 

and  measures,  499, 501 :  comparison  of, 

500. 

Wet-paper  process,  Molard's,  180. 
Wheatstone's  reflecting  stereoscope,  312. 
Whey,  (serum,)  174, 175. 
White  hair,  (coloring  of,)  228 ;  drapery,  ( co 
loring  of,)  229;  wax  in  black  varnish, 

Wollaston,  12. 

Work-room,  what  it  contains,  49,  50. 
Wortley's  (Lieut.-Colonel  Stuart)  collodion 

formulas,  80,  167 ;  developer,  116, 168 ; 

intensifier,  168. 
Wood-spirit,  104. 


Y 

Yellow  drapery,  (coloring  of,)  229. 
Yellow  tone  in  the  whites,  its  cause,  885. 


Z 

Zinc  enamel,  307 ;  white,  80T. 


INDEX  TO  THE  THIRD  EDITION. 

Tannin  Process  with  the  Alkaline  Developer,  845 

Collodion  for  do,  346 ;  Nitrate  of  Silver  bath  for  do,  347 ;  Flowing  the  plates  with 
Tannin,  348  ;  Exposure  of  Tannin  plates,  349 ;  Development  of  Tannin  plates,  349  ; 
Intensifying  of  Tannin  plates,  350. 

Wet  Collodion  Process  with  the  Alkaline  Developer,  351 

Alkaline  Developer  for  do,  352 ;  Intensifying  of  the  image,  352. 

Tannin  regarded  as  a  Sensitizer,    353 

Chromo-Photography  and  Positive  Printing  without  the  Salts  op  Silver,  356 

Sensitizing  the  paper,  357 ;  Exposing  the  sensitized  paper,  357 ;  Developing  the 
picture,  357;  Schwartz's  simple  process  for  blue  pictures,  358;  Motileff's  process, 
358 ;  Signor  Borlinetto's  process,  358. 

Process  without  the  Salts  op  Silver,  359 

Sensitizing  solution,  359 ;  Exposure,  359 ;  Fixing  solution,  360 ;  Toning  of  the 
prints,  360. 

FoTn ergill's  Modified  Albumen  Process,  362 

New  Carbon  Process  by  Mb.  Swan,  337  362 


INDEX  TO  THE 


FIFTH  EDITION. 


A 

Acid,  pyrogallic,  371,  372,  375,  380 ;  acetic, 
(glacial,)  372, 386;  sulphuric,  377;  citric, 
3S1,  398 ;  nitric,  383 ;  gallic,  388 ;  phos- 
phoric, 432. 

Ackland,  modified  Fothergill  process,  385. 

Albumen,  for  substratum,  377,  3S5. 

Alcohol,  371,  378. 

Ammonia,  carbonate  of,  380,  384,  391 ;  con- 
centrated, 885. 

Ammonium,  iodide  of,  378,  404. 

Aniline,  printing  process,  432 :  commercial, 
433. 

Anthony,  E.  and  H.  T.,  printing  frame, 

(pneumatic,)  401. 
Appendix  to  fifth  edition  of  Sunbeam,  365. 

B 

Background,  eburneum  process,  405. 
Balsam,  Canada,  419. 
Benzole,  377,  433. 

British  Journal  of  Photography,  409. 
Britton,  Mr.,  Collodio-chloride  formula,  400. 
Bromo-iodizing,  for  opal  or  porcelain  pic- 
tures, 402. 
Burgess,  Mr.,  402. 

C 

Cadmium,  bromide  of,  878,  879,  404 ;  iodide 

of,  383,  404. 
Calcium,  chloride  of,  400. 
Camera,  copying,  895. 
Caron,  Mr.,  414. 

Chapman  printing  frame,  (opal  pictures,) 
401. 

Chevrill,  Mr.,  collo-developer,  426. 

Coating  the  paper  with  collodion,  (Wothly- 
type,)  367 ;  the  plates  with  collodion, 
369,  386;  with  albumen,  387;  opal 
plates  with  collodion,  394 ;  with  collo- 
dio-chloride, 400. 

Collodio-bromide,  (process,)  389;  prepara- 
tion of,  389 ;  in  the  wet  process,  389 ; 
for  tannin  plates,  390. 

Collodio-chloride,  formula  for,  400. 

Collodion,  for  dry  plates,  373,  378 ;  bromo- 
iodizing  solution  for  (tannin  process,) 
374,  378 ;  for  the  eburneum  plate,  404. 

Collo-protosulphate  of  iron,  425;  ferric  de- 
veloper, modification  of,  426. 

Copper,  sulphate  of,  431. 

D 

Davy,  Sir  Humphry  414. 

Developer,  alkaline,  371,  374,  375.  380,  3S4, 
892;  acid,  375  ;  for  Fothergill  plates, 
388;  collodio-bromide,  890;  for  opal 
pictures,  396 ;  collo,  425. 


Development  of  the  image,  (tension,)  371, 
380;  (raisin  process,)  376;  alkaline, 
881 ;  collodio-bromide,  391 ;  opal  pic- 
ture, 396 ;  of  the  Foxtype,  432 ;  (ani- 
line process,)  433. 

Deville,  Mr.,  414. 

Distillation  of  magnesium,  415. 

Dolomite,  413. 

Duplex  pictures,  how  to  take  two  pictures 
of  the  same  person  on  the  same  plate. 
417. 

Duplicating  deflector,  418. 

E 

Eburneum  process,  402. 
Enamel,  407. 
Ether,  378. 

Exposure  of  the  tannin  plate,  371,  380,  388 ; 
opal  picture,  896 ;  (aniline  process,)  483. 


P 

Fixing,  solution,  (Wothlytype,)  368;  the 
tannin  negative,  378  ;  collodio-chloride 
picture,  401. 

Formulas  for  the  Wothlytype,  866. 

Fothergill,  process,  (modified,)  385 ;  second 
modification  of,  887. 

Fox,  Thomas,  431. 

Foxtype,  431. 

a 

Galvanic  process  for  obtaining  magnesium, 
414. 

Gelatine,  404,  426 ;  relief,  429. 
Glazing,  albumen  prints,  etc.,  407. 
Glycerine,  406. 
Gold,  ter-chloride  of,  397. 

H 

Haakman,  modified  Fothergill  process,  387. 
Helenotype,  419. 

I 

Immersion  of  Fothergill  plates  in  acetio 
acid,  387. 

India-rubber  for  substratum,  377. 

Intaglio,  metal,  (production  of,)  430 ;  print- 
ing from,  431. 

Intensification  of  the  image,  (tannin,)  3S1. 

Intensifier,  citro-nitrate,  382 ;  aceto-nitrate, 
382 ;  alkaline,  384, 392 ;  for  opal  or  por- 
celain pictures,  398 ;  Selle's,  432. 

Jron,  proto-sulphate  of,  390,  404, 

Ivorytype,  419,  420. 


INDEX. 


L 

Lea,  M.  Carey,  M.D.,  425. 
Lead,  acetate  of,  388. 

M 

Magnesium,  412,  413 ;  galvanic  process  for 
obtaining,  414 ;  process  for  obtaining 
magnesium  for  commercial  purposes, 
414 ;  reduction  of  the  chloride  of,  415 ; 
purification  of,  415. 

Marmolite,  413. 

Mastic,  419. 

Materia  medica,  413. 

Mercury,  bi-chloride  of,  398. 

Modes  of  reducing  silver  compounds.  423, 
434. 

]ST 

Negative,  to  intensify,  3T2 ;  for  the  porcelain 
picture,  394. 

O 

Opal  plates,  (to  prepare,)  393 ;  picture,  (ne- 
gative for,)  394 ;  picture,  (how  to  clarify,) 
396 ;  pictures  (by  contact  printing,)  898 ; 
plates,  (how  to  grind,)  399 ;  pictures, 
(with  a  bromo-iodized  film,)  402. 

Opaltype,  392 ;  to  take  with  the  camera,  392. 

P 

Paper,  for  the  aniline-printing  process,  432. 
Photographs,  how  to  glaze,  407,  408,  409, 

410,  411 ;  how  to  take  by  the  magnesium 

light,  412,  415. 
Photographic  News,  410. 
Photography  without  a  nitrate  of  silver  bath, 

389. 

Photo-mezzotint  printing,  427. 

Photo  printing,  427. 

Photo-relief  printing,  429. 

Pictures,  duplex,  (how  to  take  them,)  417. 

Porcelain  pictures,  392;  to  take  with  the 
camera,  392  ;  negative  for,  394 ;  how  to 
clarity,  396 ;  pictures,  (by  contact  print- 
ing,) 398  ;  plates,  (how  to  grind,)  399. 
v    Potassa,  bichromate  of,  377,  432. 

Potassium,  bromide  of,  391 ;  ferridcyanide 
of,  432. 

Preparation  of  the  sensitive  salts  in  the 
Wothlytype,  365 ;  of  the  paper  for  re- 
ceiving the  sensitive  collodion,  (Woth- 
ytvpe,)  367 ;  of  tannin  plates,  (Sut- 
ton's,) 368. 

Preservative  solution,  (tannin  process,)  375. 

Printing,  (Wothlytype,)  367 ;  on  ground  por- 
celain or  opal  plates,  399  ;  frames,  401 ; 
photo,  427 ;  photo-relief,  429. 

Process  for  printing  on  paper  without  em- 
ploying either  the  chloride,  iodide,  or 
bromide  of  silver,  and  without  develop- 
ment, 365 ;  Sutton's  tannin,  368 ;  raisin, 
873;  reliable  tannin,  377;  Pothergill, 
385,  387 ;  wet  and  dry  with  collodio- 
bromide,  389 ;  eburneum,  402 ;  for  ob- 


taining magnesium,  414 ;  aniline  print- 
ing, 432. 
Pyroxyline,  878. 

B 

Raisin  process,  plates  for,  876. 

Reduction  of  the  chloride  of  magnesium, 

415;  of  the  chloride  and  sulphide  of 

silver,  423. 

Reflectors  for  taking  pictures  by  the  magne- 
sium light,  416. 

Relief,  gelatine,  429. 

Restrainer,  (in  the  developer,)  426. 

Russell's  latest  improvements  in  the  tannin 
process,  382. 

S 

Sayce,  B.  J.,  389. 

Schnauss,  Dr.,  373. 

Selle's  intensifying  solution,  432. 

Sennotype,  402,  419. 

Sensitizing  the  film,  370 ;  solution  for  the 

aniline  printing  process,  432. 
ShiVe,  porcelain  printing  frame,  401,  418. 
Silver,  nitrate  of,  372 ;  bath,  374,  378 ;  resi- 
dues, (what  to  do  with,)  421, 422, 423, 424. 
Simpson,  Gr.  Wharton,  M.A.,  400. 
Soda,  bicarbonate  of,  371. 
Sonstadt,  Mr.,  414. 
St.  Claire,  414. 

Substratum,  (Sutton's  tannin  process,)  363, 

377 ;  wax,  402. 
Sugar,  loaf,  379  ;  grape,  390. 
Sutton's  rapid  dry  tannin  process,  868. 
Swan,  Joseph  W.,  427. 


T 

Tannin,  solution,  370,  379  ;  process,  (latest 
improvements  in,)  382 ;  bath,  (Verity's,) 
390. 

Toning,  (Wothlytype,)  368 ;  opal  or  porce- 
lain picture,  397 ;  collodio-chloride  pic- 
ture, 401. 

Tunny,  James  G.,  408. 

Turpentine,  spirits  of,  419 ;  Venice,  419. 

V 

Uranium,  sulphate  of,  432. 

V 

Varnishing,  the  negative,  373. 

W 

Washing  in  hot  water,  (Fothergill  plates,) 

387. 

Waste-residues  of  silver  and  gold,  (what  to 

do  with  them,)  421. 
Wax,  solution,  (substratum  with,)  402. 
Wenderoth,  Mr.,  402,  407,  411,  420. 
Woodbury,  Walter,  427. 
Wothlytype,  365. 

Z 

Zinc,  oxide  of,  406, 412. 


INDEX  TO  THE 


SIXTH  EDITION. 


A 

Aniline  process,  the,  443. 
Apparatus,  description  of,  497. 

B 

Blast  furnace,  the,  434. 
Burning-in  process,  the,  470. 

c 

Cabinet  portraits,  492. 
Canvas,  photographing  ont  469. 
Caoutchouc,  coating  with,  339. 
Carbon  process,  Swan's  new,  357. 
Coating  with  gelatine,  341, 
Coffee  process,  the,  483. 
Comet  stains,  459. 
Cuprammonium  process,  342. 
Cyanide  waste  solutions,  438. 

D 

Dry  processes,  improved,  482. 

E 

Elementary  photography,  1 . 
Engravings,  reproduction  of,  480. 
Enlarging  by  the  solar  camera,  443. 
Enlarging  by  the  serum  process,  477. 
Enameling,  470. 

F 

Failures ;  their  origin  and  remedies,  454. 
Filtration  and  decantation,  440. 
Fogging,  454. 

G 

Gage's  improved  photographs,  492. 
I 

Insensitiveness,  456. 
Ivory,  printing  upon,  457. 

M 

Magic  photographs,  490. 
Mezzotint  photographs,  489. 
Morphine  process,  482. 


N 

Newton's  improved  dry  processes,  494. 


P 

Photomicrography,  465. 
Photo-diaphanie  process,  476. 
Photographing  on  canvas,  469. 
Positives  in  colors,  process  for,  484. 
Printing  on  ivory,  475. 


R 

Residues,  reducing  waste,  433. 
Rotary  fan,  the,  434. 


s 

Sel  Clement,  486. 
Sensitizing  carbon  tissue,  338. 
Serrated  marks,  458. 
Serum  or  whey  process,  477. 
Solar  camera  work,  473. 
Spots,  458. 
Stains,  459. 

T 

Tea  process,  Newton's,  494. 


w 

"Wastes  and  residues,  433. 
Washed  plate  process,  482. 
"Waviness,  457. 
"White  rings,  457. 


Index  to  Elementary  Photography* 


Apparatus  necessary,  3. 
Chemicals,  4. 
Dark-room,  thQ,  5. 
Introduction,  1. 
Negatives,  how  to  take,  13. 
Positives,  how  to  take,  8, 


INDEX  TO  THE  SEVENTH  EDITION, 


B 

Bevey,  W.  T.,  512,  526. 


C 

Calotype  process,  the,  527. 
Canvas,  printing  on  painted,  512. 
Cementing  material,  517. 
Chromo-photography  or  photo-miniature, 
515. 

Collodio-chloride  of  silver,  printing  with, 
510. 


D 

Davies,  W.  H..  518. 
De  Constant,  A.,  515. 
Development,  528. 


E 

Edwards,  B.  J.,  524. 
Enlargements,  apparatus  for,  518. 


Fry,  Samuel,  514. 


a 

Greenlaw,  A.  G.,  527. 

H 

Herr  Albert,  507. 
Hughes,  Alfred,  523. 


I 

Iodizing  solution,  528. 
Ivory,  painting  on,  512. 

O 

Opal  Glass,  511. 


P 

Photo-crayon  portraits,  509. 
Photographing  machinery,  521. 
Plate,  preparing  the,  511. 
Printing,  511. 

Printing  process,  Herr  Albert's  mechani- 
cal 507 
Pritchard,  H.  Baden,  521. 


B 

Bipe  collodion  at  once,  how  to  make,  523. 


S 

Sarony,  M.,  509. 
Sensitizing,  528. 
Seventh  edition,  507. 
Simpson,  G.  Wharton,  510. 
Stippling  glass  in  the  studio,  524. 
Substratum  for  the  collodion  film,  514. 


T 

Toning,  fixing,  and  washing,  501. 
Transparent  prints,  517. 


W 

Wood  blocks,  printing  on,  526. 


INDEX  TO  THE  EIGHTH  EDITION. 


A 

Apparatus,  description  of,  568. 


B 

Blurring,  549. 


0 

Collodion,  533. 
Comets,  555. 
Collodio-Chloride,  560. 


D 

Development,  alkaline,  534. 
Developers,  organic,  537. 
Developing,  538. 
Defects  and  remedies,  545. 
Development,  stains  of  irregular,  550. 
Defects  in  paper  prints,  556. 


F 

Ferrotype,  the,  531. 
Field  work,  the  developer  for,  541. 
Field  work,  instructions  for,  541. 
Field  work,  cameras  and  lenses  for, 

544. 
Fogging,  545. 
Film,  thinness  of  the,  547. 
Film,  irregularity  of  the,  548. 
Film,  splitting  and  slipping  of  the, 

550. 

Ferrotype  plate,  the,  572. 


I 

Image,  defects  in  the,  548. 

L 

Lenses,  misplacement  of,  561. 
M 

Mounting,  566. 

N 

Negative  bath,  540. 

P 

Processes  of  Mr.  T.  C.  Roche,  540. 
Printing  on  albumenized  paper,  562. 
Printing,  medallion,  565. 

S 

Sharpness,  want  of,  551. 
Streaks,  552. 
Spot3  and  pin  holes,  553. 
Stains  and  markings,  655. 
Specimen  books,  566 

T 

Toning  bath,  562. 


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The  author,  on  leaving  England,  had  no  intentiou  of  publishing  these  lectures  ;  but, 
having  been  rewarded  by  the  American  people  as  no  lecturer  has  ever  been,  and  being 
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asm with  which  the  great  scientist  was  welcomed  by  the  cities  of  Boston,  Washington, 
Philadelphia,  Baltimore,  Brooklyn,  and  New  York,  and  the  decided  success  of  his  present 
lectures  show,  we  think,  both  their  timeliness  and  superior  merit. 

TYNDALti. — Contributions  to  Molecular  Physics  in  the  Domain 

OF  RADIANT  HEAT.  A  Series  of  Memoirs  published  in  the  11  Philosophical  Trans- 
actions "  and  "  Philosophical  Magazine,"  with  Additions.  By  John  Tyndall,  LL.  D., 
F.R.  S. ,  Professor  of  Natural  Philosophy  in  the  Royal  Institution.  1vol.,  8  vo. 
Cloth.    Price,  $5.00. 

RA.NKBN.— The  Strains  in  Trusses.  Computed  by  means  of  Dia- 
grams, with  Twenty  Examples  drawn  to  Scale.  By  Francis  A.  Ranken,  M.  A., 
C.  E.,  Lecturer  at  the  Huntley  Institution,  Southampton.  1  vol.,  8vo.  Cloth. 
Price,  $2  50. 

BASTIAN. — The  Beginnings  of  Life.    Being  some  Account  of  the 

Nature,  Modes  of  Origin,  and  Transformation  of  the  Lower  Organisms.  By  H. 
Charlton  Bastian,  M.  D.,  F.  R.  S.  2  vols.,  8vo.  With  upward  of  One  Hundred 
Illustrations.    Price,  cloth,  $5.00. 

KINGSLEY. — Town  Geology.   By  the  Rev.  Chas.  Kingsley,  F.  L.  S., 

F.  G.  S.,  Canon  of  Chester.    1  vol.,  12  mo.    Cloth.    Price,  $1.50. 

HEWITT. — Coffee :  its  History,  Cultivation,  and  Uses.   By  Richard 

Hewitt,  Jr.  Illustrated  with  a  Chromo-lithograph  of  the  Coffee  Plant,  Original  De- 
signs on  Wood,  and  a  Map  of  the  World,  showing  the  several  places  where  Coffee  is 
or  may  be  produced,  and  where  it  is  also  used.    lvol.,12mo.   Price,  $2.50. 

FIGUIER. — The  Human  Race.    By  Louis  Figuier.    Illustrated  by 

two  hundred  and  forty- three  Engravings  on  Wood,  and  eight  Chromo-lithographs. 
One  vol.,  8vo.    548  pages.   Price,  cloth,  $6.00. 

BRASSEY. — Work  and  Wages.  Practically  Illustrated.   By  Thomas 

Brassey,  M.  P.    Onevol.,8vo.    Cloth.    Price,  $3.00. 

EVANS. — The  Ancient  Stone  Implements,  Weapons,  and  Orna- 

MENTS,  OF  GREAT  BRITAIN.  By  John  Evans,  F.  R.  S.  1  vol.,8vo.  With  two 
Plates  and  four  hundred  and  seventy-six  Woodcuts.    Price,  $5.00. 

DESCHANEIi.— Natural  Philosophy :  An  Elementary  Treatise.  By 

Prof.  Deschanel,  of  Paris.  Translated  and  edited,  with  extensive  Additions,  by  J.  D. 
Everett,  D.  C.  L.,  F.  R.  S.,  Professor  of  Natural  Philosophy  in  the  Queen's  College, 
Belfast.   Part  IV.    Sound  and  Light.    With  187  Engravings.    Price,  $2.00. 

D.  APPLETON  &  CO.,  Publishers, 

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Sulphate  Iron. 


Chloride  Gold. 
Cyanide  Potassium. 
Sulphate  Quinia. 
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Mercurials. 
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COOK  &  LEE, 


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TRY  OUR  HEW  STEREOSCOPIC  LENSES 

IF  YOU  WANT  THE  BEST.   PRICE  $22  PER  PAIR. 

None  genuine  unless  our  name  is  engraved  on  them. 


Black  Walnut  Frames,  {0VALandS^e^ 
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ESTABLISHED  1865. 


LAFAYETTE  W.  SEAYEY'S  SCENIC  STUDIO, 

8  Lafayette  Place,  New  Ycrk. 


Artistic  Baciironnis. 

Possessing  the  following  merits  : 

Resemble    in  their  delicate  finish 
Mtzzotint  Steel  Engravings. 
Are  perfect  in  blending. 
Masses  of  shadows  support  and  give 
relief  to  the  figure. 

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jects. 

Have  no  "cast  iron  '  sharpness. 
Can  be  used  successfully  by  the  most 
inexperienced. 

The  newest  and  latest  styles,  and  es- 
pecially those  which  are  most  popular 
throughout  the  country,  have  been  and 
are  from  my  hands. 

See  Sarony's  well-known  photographs 
of  Jefferson  as  Rip  Van  Winkle,  Mrs. 
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Also,Gurney's  many  photographs  of 
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Plain,  Landscape,  Rembrandt,  and  Interior  Backgrounds, 
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NEW  STYLES. 

Particular  attention  is  requested  to  our  new  styles  which  are  now  coming 
into  vogue,  differing  from  former  backgrounds,  not  only  in  design,  but  in 
the  manner  of  execution.  They  are  now  in  use  in  a  few  of  the  leading 
galleries  and  are  destined  to  be  widely  popular  as  our  latest  and  best 
backgrounds.  Samples  will  be  exhibited  at  the  National  Photo- 
graphic Convention,  at  Buffalo,  in  July. 

Scenery  for  Theatres,  Public  Halls  and  Amateurs.  Panoramas,  Banners, 
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Flags  and  Decorations  for  Balls  and  Political  Associations,  TO  LET. 
Patterns,  Stencils,  and  ready-mixed  colors  for  Fresco  Painters. 

LAFAYETTE  W.  SEAVEY,  8  Lafayette  Place. 


LONG  &  SMITH, 

WHOLESALE  DEALERS  INT 

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WILSON,  HOOD  &  CO., 

No.  822  Aroli  Street, 

PHILADELPHIA,  PA. 

Request  that  the  Photographers  who  may  need  New  Lenses, 
will  try  either  a 

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Before  purchasing  any  other  make. 

We  believe  them  to  be  the  VERY  BEST  Lenses  ever 
offered  for  sale  in  the  United  States. 

We  are  willing  to  send  either  make  C.  O.  D.  on  one  week's  trial,  the 
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WE  HAVE  ALSO  A  FULL  STOCK  OF 


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We  supply  our  new  Illustrated  Price  List  to  all  applicants,  FREE. 
We  solicit  your  orders. 

WILSON,  HOOD  &  CO. 


n  t  c  a  €  0 

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N.  C.  THAYER  &  CO., 


IMPORTERS  AND  WHOLESALE  DEALERS 


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1W  &00-1IS*  I1W  fllili, 

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N.  C.  THAYER  &  CO., 
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UTICA 


SgHOTOGRAPHIC  |||§AREH0USE! 

(HAS  BEEN  ESTABLISHED  TWENTY-FIVE  YEARS.) 


Always  a  full  line  of  Goods  generally  used  by 


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ON  HAND. 

We  buy  from  "  first  hands,"  and  Manufacturers,  and  sell  at  the  lowest 
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PROMPT  ATTENTION  GIVEN  TO  ORDERS  RECEIVED  BY  MAIL. 

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O.  H.  WILLIAMSON  &  CO., 

158  Genesee  Street, 


Popular  Stock  Depot 


BALTIMORE, 


Invites  those  desiring  low  prices,  good  goods,  and  promptness  to  send 
him  their  orders* 

VOIGTLANDER'S  CAMERA  TUBES  AND  LENSES, 

C.  C;  HARRISON'S  PORTRAIT  AND  GLOBE  LENSES, 

AMERICAN  OPTICAL  COMPANY'S  APPARATUS. 

All  popular  brands  of  ALBUMENIZED  PAPER,  both  heavy  and  light,  and  guaran- 
teed to  produce  uniformly  the  most  perfect  results. 

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Porcelain  Pictures,  including  Porcelain  Glass,  Plain  and  Ground, 

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Black  Walnut,  Rosewood,  JJCT-JfJ)    M\  WjJT-TCD  JS)     For  Porcelain  Pictures 
Gilt,  and  Rustic       3$  S^J^^fiLJO^       and  Photographs. 


Silk,  Cotton  Velvet,  and  Velvet  Edge  Passepartouts  for  Porcelain  Pictures, 

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With  whatever  else  is  requisite  for  the  pursuit  of  Photography,  supplied  at  the  short- 
est notice,  and  on  the  most  favorable  terms. 

The  attention  of  Photographers  throughout  the  United  States  is  respectfully  invited 
to  the  advantages  offered  of  a  superior  quality  of  materials,  and  extensive  facilities 
for  the  execution  of  orders,  which  are  respectfully  solicited.  Orders  filled  with  care 
and  despatch,  and  sent,  if  desired,  with  hill  for  collection  by  Express,  to  any  part  of 
the  United  States.  Address 

CHAS.  A.  WILSON, 

No.  7  North  Charles  St.,  Baltimore. 


FOR  THE  SUPPLY  OF 


PHOTOGRAPHIC  GOODS,  INSTRUMENTS, 

APPARATUS,  STEREOSCOPES  &  TIEWS. 


William  B.  Holmes  &  Co., 


(Formerly  555  Broadway,) 
NEW  FIRM.   NEW  STORE.   NEW  GOODS. 


THE  BEST  HOUSE 

FOB  EVERT  DESCRIPTION  OP 

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IMPOKTERS  OF 

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A  large  assortment  of 

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Stereoscopic  Views,  Card  and  Cabinet  Photographs, 

In  Select  and  Extensive  Variety. 

From  our  large  stocks  of  the  above,  as  well  as  Cord  Stock,  Plain  and  Fancy 
Mats,  Union  Goods,  Ferrotype  Articles  Generally,  and  every 
requisite  of  the  Photographic  Art,  we  are  prepared  to 
execute  orders  to  any  extent  with 

PROMPTITUDE  AND  ON  THE  MOST  REASONABLE  TEEMS. 


MR.  J.  W.  WILLARD, 

The  well-known  and  favorite  Stock  Dealer  for  the  last  Fifteen  Yeaes,  is  now  associ- 
ated with  us,  and  will  give  his  personal  service  to  the  welfare  of  our  customers, 
while  the  interest  of  his  old  friends  will  continue  to  have  his  highest  consideration. 

It  will  continue  to  be  our  aim  to  merit  the  entire  confidence  of  all  who  deal  with 
us,  and  we  hope  to  enjoy  in  our  New  Warerooms  a  liberal  share  of  patronage. 

Price  Lists,  Illustrated  Catalogues,  Ac, 

Sent  to  any  address  on  application.  Address, 

WILLIAM  B.  HOLMES  &  CO., 
644  &  646  BROADWAY, 

Wm.  B.  Holmes.  ) 

J.  W.  Willard.  J  Cor.  Bleecker  St.,  N.  Y. 

N.  B.— The  Bleecker  Street  ad  Fulton  Ferry  Cars,  and  all  the  Broadway  Stages, 
pass  our  EstablishmeDt. 

W.  B.  H.  &  CO. 


A.  I  COLLINS,  SON  &  CO., 


f 


No.  18  SOUTH  SIXTH  STREET, 

AND 

No.  9  DECATUR  STREET, 

PHILADELPHIA. 


EVERYTHING  APPERTAINING  TO  THE  LINE 
OP  OUR  MANUFACTURES  FURNISHED 
WITH  CARE  AND  PROMPTNESS. 


Chas.  WB  Stevens, 

Importer 

Manufacturer 

and  Dealer 

IN 

PtaiKUNBrc  »iS, 

158  jj*  CHICAGO, 

The   Prompt   and  Reliable  Cash 
Warehouse, 


The  Mammoth  Stockhouse  of  the  West 


No.  259  WABASH  AVENUE,  CHICAGO,  111. 

We  take  this  opportnnity  of  thanking  our  numerous  customers  for  their  very  liberal 
patronage  since  the  great  conflagration  in  our  city,  and  it  is  with  pleasure  that  we  now  in- 
form you  that  we  have  completed  our  new  building,  and,  as  you  notice  above,  are  occupy- 
ing the  same.  We  have  spared  no  expense  or  time  in  its  construction  to  make  it  throughout 
commodious,  convenient,  and  in  every  respect  arranged  so  as  to  facilitate  rapidly  the  filling 
of  all  orders.  We  have  an  abundance  of  room,  as  our  store  is  160  feet  in  depth,  five  stories 
in  height,  and  25  feet  in  width,  thus  affording  us  ample  space  to  carry  large  stocks,  and  a 
complete  variety  of  all  the  novelties,  as  well  as  a  large  line  of  the  regular  staple  articles  used 
by  you. 

As  we  manufacture  aud  import  largely,  and  owning  the  building  we  occupy,  thus  hav- 
ing no  rknt  to  pay,  we  can  and  will  sell  at  prices  to  compete  with  any  house  in  the  West, 
while  on  many  articles  of  our  own  importation  and  manufacture  we  can  give  you  lower 
figures  than  our  competitors. 

We  manufacture  Oval  and  Square  Frames,  of  all  sizes  and  styles,  at  prices  which  defy 
competition,  and  import  direct,  Glass  Baths,  Porcelain  Ware,  Camera  Tubes,  Negative  Glass, 
Evaporating  Dishes,  Albumen  Paper,  &c,  &c  ,  all  of  which  we  get  at  first  hands,  and  can 
give  you  bottom  figures  and  guarantee  the  quality.  We  are  in  close  proximity  to  ail  the 
express  companies'  offices  and  to  the  post-office,  thus  enabling  us  to  get  your  letters  prompt- 
ly and  ship  your  orders  with  the  greatest  dispatch. 

Remember  we  have  no  rent  to  pay  and  are  headquarters  for  everything  in  the  photo- 
graphic line.  Your  orders  will  receive  our  prompt  and  personal  attention.  When  visiting 
our  city  we  would  be  happy  to  receive  a  call  from  you.         Very  respectfully, 

RICE  c&3  THOMX»S03NT, 

Chicago,  January  16th,  1873. 


HENRY  WILLIAMS, 


DEALER  IN 


EVERY  DESCRIPTION 


OF 


AND 


mm 


If  ®#  iff  Al*®fc  Bte©®tg 


PHILADELPHIA,  PA. 


impoi  t.-:r  of 


AND  MANUFACTURER  OF 


ALBUMEN  &  ARROWROOT  SALTED  PAPERS, 

PINK  and  blue  albumen  paper  constantly  on  hand 

OR  MADE  TO  ORDER, 

915  SANSOM  STREET, 

PHILADELPHIA,  PA. 

demons'  New  Albumen  Paper, 

A  superior  article  introduced  into  the  market  about  a  year  ago.  It  is  equal,  if  not 
superior  to  any  Paper  imported  ;  the  great  demand  proves  such  to  be  the  case.  It  is 
praised  by  all  who  use  it  as  to  its  keeping  white  during  warm  weather  ;  also,  for  its 
brilliancy  and  toning  qualities,  and  it  is  made  White,  Pink,  and  Blue.  Sizes  medium, 
26  x  40  and  35  x  46. 

demons'  Arrowroot  Salted  Paper 

Has  stood  the  test  above  all  other  makes  for  the  last  nine  years.  An  article  extensively 
used  for  all  Plain,  Solar,  and  Colored  Work.    Sizes,  17%  x  23,  26  x  40,  and  35  x  46. 


CLEMONS' 


Are  still  manufactured,  and  are  for  sale  by 
all  first-class  Stockdealers. 

IT.  P.  A.  Varnish, 

FOR  PLAIN  WORK  AND  RETOUCHING. 

Golden  Varnish, 

FOR  INTENSIFYING  AND  RETOUCHING. 


Jillf  E®  C Hit WB9  Bamiiaetei m9 

915  SANSOM  ST.,  PHILADELPHIA. 


Dealer  in  Photographic  and  Ferrotype  Materials  of  every  kind,  No.  1  Chambers  Street , 
corner  of  Chatham  and  Duane  Streets,  New  York, 

WANTS 

All  the  Photographers  in  the  land  to  urge  upon  their  friends  the  importance  of  having 
their  "pictures  made  before  the  substance  fade,"  or  in  more  blunt  words,  have  their  "lilcenesses 
taken"  before  they  die. — Induce 

THE  OLD,  THE  MIDDLE-AGED  AND  THE  YOUNG 

to  go  to  the  nearest  Picture-Gallery 


the  Great  Destroyer  comes,  with  his  long  train  of  diseases,  and 

THEY  ARE  ALL  SICK-A-BED, 

and  then  swept  away  ! 

Yes,  ani  all  the  Little  Babies  in  the  Country,  too, 

must  face  the  Photographer's  Lens, 

And  now  is  your  opportunity,  make  the  most  of  it.    Have  everything  ready  for  the  rush — 
keep  the  ball  rolling — provide  each  with  an  exact  image  on  which  fond  friends  and  loved 
ones  may  look  with  delight  in  after  years,  and  see  them  as  they  were 


even  after 


THEY  ABE  DEAD  AND  GONE ! 

And  when  you  have  used  up  all  your  stock  send  to  me  for  more,  and  I  will  fill  your  orders 
quicker  and  better  than  "any  other  man."  Will  send  everything  exactly  as  ordered,  and 
at  the  lowest  possible  prices — my  motto  is  the  "nimble  sixpence,"  &c. 

Terms  Cash,  or  C.  O.  D.  Should  any  one  wish  his  goods  sent  by  freight,  which  is 
much  cheaper  than  by  express,  I  shall  be  happy  to  accommodate  him  on  receipt  of  the 
amount  he  wishes  to  invest.  Small  lots  of  Card  Stock,  Envelopes,  &c,  can  be  sent  by 
mail  on  receipt  of  the  amount  and  postage  at  the  rate  of  one  cent  for  every  two  ounces, 
which  is  much  cheaper  than  any  other  way. 

ANDREW  H.  BALDWIN, 

No.  1  CHAMBERS  STREET, 

Corner  Chatham  and  Duane  Sts., 

NEW  YORK. 

Formerly  connected  with  Holmes,  Booth  &  Haydens,  and  afterwards  with  the 
Willards  &  Thayer. 


1843.]   The  "Old  Reliable."  Established  30  Years.  [1873. 


P.  SMITH  &  CO., 

WHOLESALE  DEALERS  IN 


[ofogtrajijfc  mu\ 

CHEMICALS,  APPARATUS,  TUBES, 

y^LRTISTS'  yV\.ATERIALS,  ^"C. 
SPECIALTY. 


FOR.  THE  TRADE  ONLY. 


Copying  and  Enlarging  Old  Pictures, 

Copies  Finished  in  India  Ink,Water  or  Oil  Colors. 


A  Pamphlet  on  Enlarging  and  Copying  furnished  on  application. 


a®  SS  W©i 


EDWARD  MEAD  &  CO., 


DEALERS  IN  EVERY  DESCRIPTION  OP 


AND 


DEPOT  FOR 


MEAD'S  I.  X.  L  PLATES, 

Chemicals,  Cases,  Glass,  Mattiiigs,  ^Preservers,  jilbums, 
JFrames,  ^Photograph  tPaper, 

CAMEBA  TUBEBj  APPARATUS, 

AND  EVERYTHING  PERTAINING  TO  THE  ART, 

No.  304  North.  Fourth  Street, 


SAINT  LOUIS. 


D.  J.  RYAN'S 


SOUTHERN 


liiii 


AND 


FERROTYPE 


WHIM  DEPOT. 


9 


SAVANNAH,  GA 


First-Class  Stock  at  Northern  Prices, 


Saving  Time,  Freight,  Insurance,  Drayage, 
etc.,  etc. 


IN  THE 


THREE  GREAT  CITIES 

OF 

CINCINNATI,  ST.  LOUIS  AND  LOUISVILLE. 

Onr  purchases  are  made  in  the  largest  quantities  and  of  the  Manufactu- 
rers and  Importers,  and  consequently  we  are  always  able  to  offer  bargains  to 
our  customers.  It  is  well  known,  too,  that  we  keep  the  best  goods,  and  deal 
fairly  and  honestly  with  all  who  buy  of  us.  We  supply  everything  used  in 
the  business.  Address, 

GATCHEL  &  HYATT,  108  West  5th  St.,  Cincinnati,  0. 
GATCHEL  &  HYATT,  18  North  4th  St.,  St.  Lords,  Mo. 
GATCHEL,  HYATT  &  CO,,  89  Jefferson  St.,  Louisville,  Ky. 


1873. 


The  rapid  progress  which  has  been  made  in  our  art  of  late  makes  it  com- 
pulsory on  the  part  of  the  photographer  who  would  excel,  or  even  keep  pace 
with  it,  to  read  and  study  more  than  he  has  ever  done  before.  We  are  ena- 
bled to  offer  you  for  your  instruction,  such  a  catalogue  of  publications  this 
year,  as  has  never  been  offered  to  the  world  before.  It  embraces  full  inform- 
ation from  the  most  competent  sources  upon  every  branch  of  your  vocation, 
and  you  cannot  invest  money  that  will  return  you  more  largely  and  quickly 
than  what  you  invest  in  a  selection  of  works  from  the  following 

A.  — The  Philadelphia  Photographer,  the  oldest,  best,  and  most 
popular  Photographic  Magazine  in  America.  It  is  the  photographer's  true 
and  tried  advocate,  and  has  done  more  to  elevate  photography,  and  worked 
harder  to  put  money  into  the  pockets  of  its  patrons  than  any  magazine  of 
the  art  was  ever  known  to  do.  No  money,  labor,  or  time  is  spared  to  make 
it  all  that  a  photographic  journal  should  be.  Each  number  is  embellished 
by  a  fine  specimen  of  photography,  intended  to  set  up  before  the  fraternity 
examples  worthy  of  imitation.  You  actually  lose  money  if  you  do  not  have  it. 
Subscription  price,  $5  a  year  ;  $2.50  for  six  months,  in  advance.  Specimen 
copies,  50  cents. 

B.  — The  Skylight  and  the  Dark-Room.  By  Elbert  Anderson, 
operator  at  Kurtz's  studio,  New  York.  This  is  the  most  beautiful  and  elabo- 
rate work  on  the  art  ever  published.  It  contains  nearly  250  pages — large, 
square — twelve  photographs  made  by  the  author  to  illustrate  the  lessons  of 
the  work,  and  almost  two  hundred  fine  wood  cuts.  The  author  gives  more 
information  in  a  concise  shape  than  any  of  his  predecessors,  and  being  a 
practical  operator,  gaining  his  daily  bread  under  the  skylight  and  in  the- 
dark-room,  he  tells  his  story  in  such  a  way  as  to  make  it  most  plain  to  the 
beginner,  as  well  as  most  valuable  to  the  more  practiced.  ^  It  is  a  magnificent 
work,  and  as  good  and  useful  as  it  is  magnificent.  Price,  in  cloth,  gilt,  post- 
paid, $4. 

C.  — Photographic  Mosaics.  The  1873  edition  excels  all  of  its  seven 
older  brethren.  The  list  of  articles  is  made  up  of  original  contributions, 
written  especially  for  its  pages,  on  all  departments  of  the  art,  wholly  by 
practical  men  who  are  only  heard  from  once  a  year  in  this  way. 

The  poser,  the  dark-room  man,  the  printer,  the  toner,  the  painter,  the 
landscapist,  the  retoucher,  the  glass  cleaner,  the  business  photographer,  and 
the  amateur,  will  find  much  in  Mosaics  of  value  to  them  this  year.  144  pages 
as  usual,  paper  cover,  50  cents.  Cloth,  $1.  A  few  copies  of  former  editions, 
from  1866,  at  same  price. 

D.  — The  Ferrotyper's  Guide.   A  new  work  on  the  Ferrotype. 

Our  editions  of  Mr.  Trask's  book  being  exhausted  we  have  replaced  it  by 
the  FerrotyperJs  Guide,  which  we  will  supply  at  best  rates  to  dealers  and 
others. 

An  elegant  Ferrotype  of  card  size,  made  by  Estabrooke  personally, 
accompanies  each  book. 

Its  mission  is  not  to  tell  but  to  teach  everything  necessary  to  enable 
even  a  novice  to  make  good  ferrotypes,  and  to  get  better  prices.  Price, 
paper  cover,  75  cents, 

E.  — Bigelow's  Album  of  Lighting  and  Posing.  This  is  not  ex- 
actly a  book,  but  a  collection  of  24  large  Victoria  size  photographic  studies 
in  lighting  and  posing,  made  especially  to  teach  how  to  light  and  pose  ordi- 
nary and  extraordinary  subjects  in  all  the  plain,  fancy  "  Rembrandt "  and 
"  Shadow  "  styles.  It  is  accompanied  by  an  explanatory  key  of  instructions, 
together  with  a  diagram  for  each  picture,  showing  how  the  sitter  and  the 
camera  were  placed  in  the  skylight,  their  relation  to  the  background,  and 
what  blinds  were  opened  and  closed  at  the  time  of  the  sitting.  It  almost 
supplies  a  rule  by  which  you  can  quickly  tell  how  to  manage  every  subject 
that  comes  to  you.  The  studies  are  mounted  on  folding  leaves,  so  that  twelve 
can  be  examined  at  once.   Price,  in  cloth,  gilt,  $6,  post  paid. 


F.  — Wilson's  Landscape  Studies.  An  album  of  landscape  studies 
in  style  similar  to  Bigelow's  Album,  containing  ten  5x8  views,  with  the 
formula,  &c,  by  George  Washington  Wilson,  Esq.,  the  renowned  Scotch 
landscape  photographer.    A  splendid  work.   In  cloth,  gilt,  $4. 

G.  — Vogel's  Handbook  of  the  Practice  and  Art  of  Pho- 
tography. Treats  on  all  matters  of  photographic  practice  in  every  depart- 
ment. Decidedly  a  most  practical  and  useful  photographic  work  by  a  popu- 
lar German  author.  Full  of  illustrations,  and  has  four  photographs  showing 
the  various  methods  of  lighting  the  face.   Price,  $3.50,  post  paid. 

H.  — How  to  Paint  Photographs  in  Water  Colors.  A  practical 
Handbook  designed  especially  for  the  use  of  Students  and  Photographers, 
containing  directions  for  Brush  Work  in  all  descriptions  of  Photo-Portraiture, 
Oil,  Water  Colors,  Ink,  &c.  By  George  B.  Ayres,  Artist.  Third  edition. 
Differing  largely  from  previous  editions.    Price,  $2.00. 

The  new  chapter  on  retouching  negatives,  contributed  by  the  distinguished 
artist-photographer,  Mr.  William  Kurtz,  of  New  York, is  a  conspicuous  feature 
of  this  edition  ;  and  is  needed  by  every  photographer  who  desires  to  accom- 
plish this  beautiful  process.   It  is  alone  worth  the  price  of  the  book. 

|.— Pictorial  Effect  in  Photography.  By  H.  P.  Robinson,  London. 
English  edition.  A  splendidly  illustrated  work,  teaching  how  to  pose  and 
light  the  subject,  the  rules  of  composition,  &c,  &c.  $3.50. 

J.— How  to  Sit  for  Your  Photograph.  This  is  a  fine  little  work  of 
48  pages,  written  by  the  wife  of  a  celebrated  New  York  photographer,  for 
the  purpose  of  educating  the  public  on  the  all-important  subject  of  sitting 
for  a  picture,  and  to  assist  the  photographer  in  securing  the  best  possible 
results.  It  is  bound  in  cloth  at  60  cents  per  copy,  and  paper  cover  30  cents, 
retail. 

K.— Lookout  Landscape  Photography.  By  Prof.  R.  M.  Linn, 
Lookout  Mountain,  Tenn.  A  pocket  manual  for  the  outdoor  worker,  and  full 
of  good  for  every  photographer.  75  cents.  The  book  for  the  season.  Be  sure 
to  get  it, 

L. — Himcs*  Leaf  Prints;  or,  Glimpses  at  Photography.  By 

Prof.  Charles  F.  Himes,  Ph.  D.  Full  of  useful  information  for  the  photo- 
graphic printer.   Illustrated  with  a  whole-size  photograph.   Cloth,  $1.25. 

M-—  The  American  Carbon  Manual.  By  Edw.  L.  Wilson.  A 
complete  manual  of  the  Carbon  process  from  beginning  to  end.  With  a  fine 
example  by  the  process.   Cloth,  $2.00. 

N  .—Ayres'  Chart  of  Photographic  Drapery.  This  is  a  photo- 
graph of  forty-two  pieces  of  cloth,  of  all  the  colors  and  shades,  handsomely 
mounted  on  a  card.  It  should  be  hung  in  every  reception-room,  to  show  your 
customers  what  color  dresses  to  wear,  and  to  show  you  what  sort  of  back- 
grounds and  accessories  to  use.   Price,  $2.00, 

O.— "The  Photographer  to  his  Patrons."  A  splendid  little 
twelve-page  leaflet,  which  answers  all  vexatious  questions  put  to  you  by  your 
sitters,  and  serves  as  a  grand  advertising  medium.  It  is  for  photographers  to 
give  away  to  their  customers.  Send  for  a  copy  and  an  illustrated  circular. 
Over  500,000  already  sold  and  in  use  all  over  the  country.  $20.00  for  1000. 
$35.00  for  2000,  and  so  on.  Printed  and  supplied  in  English,  German  and 
Spanish. 

P.— Pretty  Faces.  A  leaflet  much  smaller  than  "  The  Photographer  to 
his  Patrons,"  for  the  same  purpose,  but  costing  less,  viz. :  1000  copies,  $10.00; 
2000  copies,  $17.50,  and  larger  orders  at  less  rates. 

Q.— The  Year-Book  of  Photography.  By  G.  Wharton  Simpson. 
English  edition.  Similar  to  Mosaics,  and  full  of  good,  short,  practical  arti- 
cles.  50  cents.   1869, 1870, 1871, 1872,  and  1873  now  on  hand. 

R.-~ Elbert  Anderson's  Photo-Comic  Allmy knack  for  1873. 
Being  a  complete  Almanac,  full  of  witty  sayings,  jokes,  puns,  stories,  etc., 
etc.  Profusely  illustrated  with  comic  and  original  sketches,  yet  all  inter- 
spersed with  much  practical  matter  of  value  to  every  photographer.  Issued 
May,  1873.   Price,  75  cents. 

To  save  writing,  photographers  may  order  the  above  of  us  by  the  mar- 
ginal letters,  thus,  "  Please  send  us  one  copy  of  each,  book  A,  B,  K,"  &c, 
&c,  Any  of  the  above  sent,  post  free,  on  receipt  of  price,  by  any  dealer,  or 
by 


BENERMAN  &,  WILSON,  Photo.  Publishers,  PHILADELPHIA,  PA, 


THE 


Hill  PUMPI 1111 

In  Baltimore,  HVEcl., 

— IS  THE  — 

HEADQUARTERS 

FOR 


teogapMr  flatmate 


OP  SUPERIOR  EXCELLENCE, 

Practical  PlotoppMc  Piications, 

First  Class  Trade  Photocraphy, 

FINE  SELECT  STEREOSCOPES  AND  VIEWS, 

STEREOPTICONS  AND  SLIDES. 


RIOHAED  WALZL,  Publisher  and  Proprietor, 

BALTIMORE,  MD. 


Send  for  a  copy  of  the  New  National  Illustrated  Price  List, 
a  book  of  180  pages  valuable  reading  matter,  and  a  handsome 
Photographic  Portrait,  free  on  application. 


MILWAUKEE. 


J.  H.  TESCH  &  CO., 

11  and  13  SPRING  STREET. 


A  FULL  LINE  OF 


EMBRACING 


ALBUMENIZED  PAPER, 

ALBUMS, 

Mouldings,  Frames, 

—  AND  — 

VIEWS, 

Hand-  S  copes, 

&c,  &cM  &c 


^f**Our  Prices  will  be  as  low  as  those  of  any  other  House,  while  in  the 
promptness  and  accuracy  of  filling  orders,  we  are  excelled  by  none. 

SPECIALTY. 

Silver  waste  refined  in  our  own  Laboratory  and  under  our  ownj  super- 
vision.  Returns  made  within  two  weeks.    Satisfaction  guarantee*}. 
Send  for  Price-Lists. 


JAMES  W.  QUEEN  &  CO., 

IMPORTERS  AND  MANUFACTURERS  OF 

ATHEMATICAL,  jD  PTICAL, 

AND 

601  Broadway,  New  York, 
924  Chestnut  St.,  Philadelphia. 

AGENTS  FOR 

W.  &  L.  E.  GURLEY'S  Compasses,  Transits  and  Levels. 

J.  KERN'S  Swiss  Drawing  Instruments. 
R.  &  J.  BECK,  London  Opticians. 


DRAWING  INSTRUMENTS, 

Drawing  Materials  and  Papers,  Transits,  Levels,  Compasses, 
Tape  Measures,  Rules. 

MICROSCOPES,  OPERA  CLASSES, 

Spy  Glasses,  Telescopes,  Stereoscopes,  Microscopic  Apparatus, 
Microscopical  Preparations. 

MAGIC  LANTERNS, 

Stereopticons,  Dissolving  Views,  with  Pictures  from  all  parts  of 
tbe  world,  and  upon  all  subjects. 

THERMOMETERS,  BAROMETERS, 

Rain  Gauges,  Air  Pumps,  Electric  Machines,  Magnetic  Appa- 
ratus, Globes,  School  Apparatus,  Sec,  &c. 

The  following  Manuals  sent  on  receipt  of  10  cents  each. 

Part  1st— Mathematical  Instruments,  155  pages. 
Fart  2d— Optical  Instruments,  107  pages. 
Part  3d — Magic  Lanterns  and  Stereopticons,  88  pages. 
Part  4th— Philosophical  Instruments,  64  pages. 


8TEREOPTIOOMS, 


1 


BsmoLvgm  view  apparatus, 


AND  PICTURES. 


9 


LENSES  FOE  RETOUCHING, 


ACHROMATIC  STEREOSCOPES, 


AND 


STJEMEOSCOJPIC  VIEWS  IN  AJLJL  JPAMTS  OF  TMJE 


MADE  AND  FOR  SALE  BY 


JAMES  W.  QUEEN  &  CO., 

601  Broadway,  New  York, 
924  Chestnut  Street,  Philadelphia. 


Catalogue  of  88  pages  sent  on  application. 


RICKEY  &  DUNN, 


M 


'9 


MOULDINGS, 


mi  i  square  mnm 


JA.ATS  AND  J^ASSEPARTOUTS, 


No.  10  EAST  THIRD  STREET, 


WHOLESALE 

* 

Photographic  Itqck 

 MANUFACTURERS  OF  

FRAMES,  STEREOSCOPES  &  MOULDINGS, 


IMPORTERS  AND  PUBLISHERS  OF 


&c,  &c,  &c. 


DEALERS  IN  EVERY  ARTICLE  USED  IN  THE 

PICTURE,  FEAME  AND  PHOTOQRAPH  BUSINESS. 


115  Washington  St.,  Boston. 

SEND  FOR  PRICE  LISTS,  -fg^ 


:  jhotojgrajfe  J'mpmhmg  wnu  for  $fim$. 


BLESSING  &  BRO., 

174  Tremont  St.,  Galveston, 


KEEP  A  FULL  SUPPLY  OF  FHESH 


Ferrotype  &  Photographic 


Apparatus,  S 


From  the  most  reliable  Manufacturers  and  Importers. 


Lenses, 

Camera  Soxes, 
Gem  Cameras, 
Stands, 
Baths, 

Trays  and  Pans, 
Printing  Frames, 
Negative  Boxes, 
Posing  Chairs, 
Scales  &  Weights, 


Diamonds,  Plates, 
Evaporating  Dishes,  Genuine  B.P.C.  Glass, 
Mortars  &  Pestles,    French  Glass, 


Funnels, 
Collodion  Vials, 
Graduates, 
Backgrounds, 
Head  Bests, 
Union  Goods, 
Cases, 


Porcelain  Plates, 
Card  Mounts, 
Card  Board, 
Gem  Mounts, 
Paper  Matts, 
Standard  Matts, 
Frames  of  all  kinds, 


Picture  Cord  and  Nails, 
STEREOSCOPES   A_NX>  VIEWS, 

FROM  25   CENTS  TO  $10  EAOH- 

PAPERS,  Morgan's,  Trapp  &  Munch,  S.  &  M.Dresden,  Swiss  Pink,  &c. 

FILTER  PAPER,  ADHESIVE  PAPER, 

Atwood'S  Alcohol,  Ether,  Collodion  (Blessing  &  Bros,' is  always 
fresh  and  none  better),  Iodides,  Bromides,  Silver,  Varnishes, 

&C,  &C.  In  fact  everything  kept  in  a  first-class  Furnishing  House. 


Send  your  orders  to  us  and  save  freight  and  annoyance. 
All  Apparatus,  and  the  most  of  other  goods  at  manufacturers'  prices. 
Send  for  price-lists. 


HALE,  KILBURN  &  CO., 

Wholesale  Manufacturers,  for  the  Trade  only,  of 

WALNUT  FRAMES,  MOULDINGS,  BACKING, 


Also,  Sole  Manufacturers  of  the  Original 

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PATENTED  OCTOBER  24,  1871. 
CAUTION. — All  persons  are  hereby  cautioned  against  infringing  upon  our  rights, 
under  the  above  patent,  according  to  law. 


We  make  a  specialty  of  manufacturing  Frames  in  great  variety  for  the 
PHOTOGRAPH  trade.    Particular  attention  is  drawn  to  our 

NEW  STYLES  PATENTED  SOLID  OVALS, 

which,  for  beauty,  quality,  and  price,  have  gained  the  highest  reputation 
in  the  market.    (See  Cut.) 

The  Trade  Supplied  at  Wholesale  Prices  with 

PICTURE  NAILS,  CORD  &  TASSELS,  SCREW  EYES,  &c. 

jfcg~Ask  your  Stockdealer  for  our  Goods.    If  unable  to  obtain  them,  send  direct  to  us. 
PKICE-LIST  FURNISHED  ON*  APPLICATION. 

Warerorms  and  Factory: 
48  and  50  NORTH  SIXTH  ST.,  and  615,  617,  619  and  621  FILBERT  ST., 

PHILADELPHIA. 


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